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Design and development of methodology for construction of thin white topping for rural roads in India

Design and development of methodology for construction of thin white topping for rural roads in... A large proportion of villages in India have been connected with water bound macadam (WBM) or bituminous roads. Rural roads usually have a low volume of traffic, consisting mostly of light transport vehicles with less frequency of heavy traffic. Maintenance of these roads is neglected because of the paucity of funds and the created road asset is in deteriorated condi- tion. The non-availability of suitable soil and aggregates has made projects unviable and cost prohibitive. This aggregate scarcity will increase further as a result of environmental conservation and restriction on mining. There is a need to develop alternative pavement designs to construct sustainable and durable rural roads. The stabilization of soil/aggregate is being used worldwide towards optimal usage of scarce resources. The concepts of soil/aggregate stabilization and Cold In Place Recycling technique provide a comprehensive solution for rehabilitation of existing road and greenfield road construction. Cold In Place Recycling process allows usage of locally available marginal materials. The stabilization process can use a wide range of stabilization agents such as soil-aggregate mix, lime, cement, fly ash, foamed bitumen, emulsion, polymers, and other proprietary chemical stabilizers. Two rural roads are identified under Mukhya Mantri Gram Sadak Yojana Research and Development Scheme. Pavements are designed considering cement treated base. These roads are constructed using the Cold In Place Recycling technique. The existing water bound macadam (WBM)/deteriorated bituminous surface is stabilized with cement. Bituminous concrete and Thin White Topping are provided as wearing course. The performance of pavement is evaluated after 2 years of construction. Also, the balance life of the pavement is checked and the results are satisfactory. The stabilized pavements offer superior strength and longevity, even in extreme climatic conditions, and provide better per - formance. The design charts for Thin White Topping for rural roads are not available, hence the design charts for Thin White Topping of M30/M35/M40 grade concrete on Cement Treated Base of varying thickness and different subgrade CBR are prepared based on IRC 62-2014 for traffic less than 50 CVPD, 51 to 150 CVPD, and less than 450 CVPD. These charts are ready to use and act as a guide to the Field Engineers. The optimum thickness of Thin White Topping can be selected from the chart for known subgrade CBR and Traffic. The effect of variation of CTB thickness on Thin White Topping thickness can be determined from the chart. Keywords Cement treated base (CTB) · Thin white topping (TWT) · Cold in place recycling (CIPR) · Rural roads · Stabilization · California bearing ratio (CBR) Introduction A large proportion of villages in India have been connected with water bound macadam (WBM) or bituminous roads. Rural roads usually have a low volume of traffic, consist- ing mostly of light transport vehicles with less frequency * R. Y. Patil of heavy traffic. Mostly flexible pavements with granular patilry.civil@coep.ac.in subbase and base having thin bituminous carpet as wearing M. S. Ranadive course are adopted in rural roads, which deteriorate dur- msr.civil@coep.ac.in ing monsoon seasons leading to costly maintenance every Civil Engineering Department, College of Engineering Pune, year. Maintenance of these roads is neglected because of the Pune, Maharshtra, India Vol.:(0123456789) 1 3 245 Page 2 of 26 Innovative Infrastructure Solutions (2022) 7:245 paucity of funds and the created road asset is in deteriorated Thin White Topping for rural roads are not available. The condition. The non-availability of suitable soil and aggre- goal of present research is to design and develop methodol- gates has made projects unviable and cost prohibitive. This ogy for construction of Thin White Topping for rural roads. has necessitated the exploration of other alternative pave- The development of these charts can be useful for Field ments. The stabilization of existing local available material Engineers. Thin White Topping design charts with variable provides an effective solution. Wu et al.[1 ] constructed six thickness of cement treated base and different subgrade CBR full scale accelerated pavement testing tracks with cement are developed for rural roads. treated base with thin white topping and after testing in laboratory concluded that, the Roller Compacted Concrete pavement structures over adequate base support would have Cement treated base with cold in place superior load carrying capability hence thin RCC-surfaced recycling technique pavement structure recommended as a pavement design alternative in low-volume pavement design. Ramachandra, Quality road aggregates have become rare and costly in [2] studied a technology demonstration project in Banglore many places in India due to the massive construction activi- to demonstrate the advantages of white topping by making ties required for the development of new infrastructure use of the advances in construction equipment and methods facilities. It is a need to look for ways of improving lower and concluded that concrete roads and white topping provide quality materials that are readily available for use in road- a sustainable as well as cost-effective option for pavement way construction. Cement/ lime treatment has become an construction. The guidelines for construction of cement con- accepted method for increasing the strength and durability crete roads are presented by. Kadiyalie [3] which includes of soils and marginal aggregates. Soil cement is a highly advantages and disadvantages of concrete roads, techno- compacted mixture of soil/aggregate, cement, and water. The economic aspects, properties and testing of concrete, design advantages of the soil–cement mixture are great strength and mixes, drainage considerations, specifications for subgrade, durability combined with low first cost. subbase, concrete pavement design, joints, quality control, Advantages of Cement stabilization are— a special technique of concrete paving, and use of fly ash in concrete roads. Skanda Kumar et al. [4] conducted perfor- • Cement is easily available mance evaluation studies to determine the functional and Cost is relatively low structural condition of a white topping overlay. Li and Van- • Highly durable denbossch [5] developed three dimensional finite-element Weather resistant and strong model for thin white topping subjected to environmental • Reduces swelling characteristics of the soil and wheel loads and concluded that the maximum tensile stress is induced in the wheel path and at the bottom of the Many existing rural roads in India are unpaved low vol- PCC overlay, which results in a longitudinal crack. S K ume roads. Heavy rainfall and floods affect almost all these Bagui [6] developed design curves to estimate thickness of roads frequently. The roads are severely damaged due to soil–cement base and that of the soil–lime subbase for dif- floods, currents, and wave action. This situation requires ferent traffic and different values of modulus of soil–cement the maintenance of these roads frequently. These adverse and soil–lime mix. Kumar et al. [7] provides a cost-effective effects together with inadequate compaction significantly solution to problematic clayey soils by adding jute fibres. impair the durability of these roads. The ultimate effect is Erdawaty et al. [8] presented that the addition of asbuton comparatively low subgrade strength and eventually higher with waterglass could increase soil’s load capacity and pavement thickness if paved roads are to be constructed. reduce the settlement of soft soils. The design charts for flex- Based on this treatment of locally available materials has ible pavements using cement treated base are published in become necessary for satisfactory and economic construc- IRC 37-2018 [9]. Guidelines for The design of plain jointed tion of roads in these regions. Cement stabilized bases or rigid pavements for highways are published in IRC 58-2015 lime stabilized sub-bases may be provided for the construc- [10], and guidelines for design and construction of cement tion of rural roads for low volume light traffic. concrete pavements for low volume roads are published in An increasing emphasis has been placed on the use of sta- IRC SP 62-2014 [11]. Harrington et.al [12] provides a guide bilized pavement materials in recent years. Using stabilizing for evaluating existing pavements to determine if they are agents, low-quality materials can be economically upgraded good candidates for concrete overlays, selecting the appro- to the extent that these may be effectively utilized in the priate overlay system for specific pavement conditions, and pavement. Stabilized pavement materials are generally used managing concrete overlay construction work zones under in the pavement structure as base courses and sub-bases. In a traffic. Guidelines for conventional and Thin White Topping layered system of elastic materials, where the overlying lay- are published by IRC 76-2015 [13]. The design charts for ers have higher moduli of elasticity than underlying layers, 1 3 Innovative Infrastructure Solutions (2022) 7:245 Page 3 of 26 245 tensile stresses are developed at the interfaces between the Pavement design layered materials. This layered system analysis is commonly presumed to apply to a pavement where stiffer materials are The Thin White Topping (TWT) Pavements are designed as used in the upper layers. Since many stabilized materials per IRC SP 62-2014 [11]. are relatively weak in tension, any type of rational design procedure must take their tensile strength into account. (A) Name of Road: Sanaswadi Dhanore Road Tal. Shirur The key machinery required for the CIPR technique is— Dist. Pune Streau Master (Automatic Cement Spreader), recycler, pad foot roller, grader, etc. Initial design 283 Grade of concrete M30 traffic (A) CVPD Design life 20 years Design flexural 4.22 MPa Field trial stretch (n) strength = 90 days strength consid- Two roads having different types of traffic, geography and ered f = 1.1 × existing soil conditions have been selected from Pune district 0.7 × √fck in Maharashtra State under the Research and Development Traffic 5% Poisson’s ratio of 0.15 growth rate concrete Scheme of Mukhya Mantri Gram Sadak Yojana. (r) −6 Reliability 60% Coefficient of ther - 10 × 10 per (1) Sanaswadi to Dhanore Road Taluka Shirur District mal expansion (α) °C Pune % Cracking 40% Trial Concrete 200 mm (2) Pimpre to Ozare Road Taluka Indapur District Pune at the end of Thickness = with CTB design life 200 mm Preliminary data Fatigue 10% Transverse Joint 2.00 m check spacing (L) criteria for Preliminary data like subgrade soil, surface condition, car- a vehicleex- riageway width, crust thickness, rainfall and drainage con- ceeding dition have been collected. The preliminary data of the two 50 kN Wheel load road sites are as tabulated below (Table 1). Wheel load 50 kN Temperature Zone III (Maharash- Laboratory tests are conducted on subgrade soil for clas- for a single tra) sification of soil, proctor density, and CBR. Unconfined axle with Compressive Strength (UCS) is strength indicator of cement dual wheel treated base (CTB). It is conducted on existing WBM mate- Spacing of 310 mm rial with 4% cement content. According to IRC: 37-2018 [9] Wheel 7 days UCS of cement stabilized base should be minimum Tyre pres- 0.80 MPa sure (p) 4.5 to 7 MPa. The UCS test results fit in this limit, speci- fied by the Indian Road Congress (IRC). The laboratory test results are given in Table 2. Table 1 Preliminary data of Sr. No. Road name Length km Initial Traf- Carriage- Surface condition Crust two road fic CVPD way width thick- m nessmm 1 Sanaswadi To Dhanore 1.80 283 3.75 Deterioted BT 200 2 Pimpri To Ozare 0.50 102 3.00 WBM 100 Table 2 Subgrade soil properties and UCS of WBM with 4% cement Sr. no. Road name Subgrade soil classification MDD KN/m OMC % CBR % (WBM + 4% Cement) 7-day Gravel % Sand % Silt and Clay % UCS MPa 1 Sanaswadi To Dhanori 25.08 71.33 3.60 19.71 11.00 6.79 5.6 2 Pimpri To Ozare 28.03 67.70 4.27 21.67 10.81 8.00 1 3 245 Page 4 of 26 Innovative Infrastructure Solutions (2022) 7:245 Fig. 1 Typical cross section of rigid pavement A typical cross section of rigid pavement is shown in Initial traffic (A): 102 CVPD, Design thickness of M30 Fig. 1. grade TWT: 150 mm with CTB 200 mm Edge Stress using Westergaard equation Subgrade CBR: 8% σ = 2.16 MPa • Modulus of subgrade reaction for subgrade CBR 8% and Temperature stress (σ ) is calculated by equation (1) 200 mm CTB (k) = 237 MPa/m te • Edge stress σ = 3.27 MPa 0.67 × C ×  ×ΔT × E E ×  ×ΔT = − Temperature stress σ = 0.61 MPa (1) te te 2 3 × 3.91 • Combined stress (σ) = 3.88 MPa. C = correction factor based on L/l = 0.34 Since calculated combined stress (3.88 MPa) is less than l = radius of relative stiffness. design flexural strength (4.22 MPa), the design is safe. α =: coefficient of thermal expansion ΔT=: temperature differential °C E = Modulus of Elasticity of concrete in MPa Construction methodology σ = 0.16 MPa te Combined stress (σ) = wheel load stress + temperature Cement treated base stress σ = 2.16 + 0.16 = 2.32 MPa < 4.22 MPa The existing road is having a WBM/deteriorated bituminous Check for Fatigue criteria with 60% reliability as given surface. To utilize existing coarse aggregates Cold in Place by Eq. (2) Recycling (CIPR) technology has been adopted for the con- −2.222 SR struction of CTB. The machinery required for CTB work Log N = (2) 10 f 0.523 is Streau Master (Automatic Cement Spreader), Recycler, Pad foot roller, and grader. The CTB thickness requirement N = Fatigue life with combined wheel load + temperature f- is 200 mm, hence additional Wet Mix Macadam (WMM) stresses. material laid of required thickness. 4% Cement by weight SR = Sress Ratio = combined f lexural stress/f lexural basis is spread on the coarse aggregate surface with help of strength. Streau Master. The width of the spreader is 2 meters. Hence, SR = 0.56. cement is spread in half lane width in one go. Recycling of Allowable repetitions given by Eq. (2) N = 15,129,009. WBM/WMM material is done with the help of a Recycler. For rural roads fatigue criteria checked for 10% of CVPD Recycler can recycle material up to 500 mm depth. For the over design life. trial stretch, 200 mm thick CTB is required; accordingly, the Expected repetitions (N) = 10% of Total traffic over A×(1+r) −1 depth of recycling is adjusted, so that compacted 200 mm design life = 10% of . thick CTB is obtained. (Fig. 2) Water is added as per opti- N = 362,072 < N . mum moisture content (OMC) requirements at the time of As the cumulative fatigue damage factor (N/N ) is less recycling. After recycling the surface is rolled with a pad than 1; hence the design is safe. foot roller to achieve the required compaction. The surface is graded to the required profile and rolled with the help of (B) Name of Road:—Pimpre Ozare Road Tal. Indapur Dist. a smooth wheeled roller. Curing of CTB is done for 7 days Pune before laying of wearing course. 1 3 Innovative Infrastructure Solutions (2022) 7:245 Page 5 of 26 245 Fig. 4 Texturing of concrete Fig. 2 Recycling of base course with Recycler Fig. 5 Joint cutting and filling with sealant Fig. 3 Laying of PQC The curing of concrete is done for 14 days by ponding/plac- ing wet gunny (jute) bags. Light vehicles are allowed after 14 days. Heavy vehicles are allowed after 28 days. Wearing course Channels of required sizes are placed on the outer edge side Problems during construction of the carriageway. M30 grade Pavement Quality Concrete (PQC) of required thickness as per design has been provided (1) During constructing the CTB roads, it is necessary to divert traffic to alternative nearest road otherwise sur - on CTB (Fig. 3). A polythene sheet of 125-micron thickness has been laid on CTB before laying of PQC. Concrete is face profile of the freshly constructed CTB layer will get disturbed. properly compacted with the help of needle vibrators. The finished surface of the concrete is broomed with the help of (2) A set of machinery is required for construction CTB using the CIPR technique, hence it becomes uneco- a wire broomer to obtain texturing of 1.5 mm depth (Fig. 4). The transverse contraction joints at the spacing 2  meter nomical to construct smaller stretches. (3) The construction of the road should be in a continuous center to center and 3 to 5 mm width sawed to the depth 1/3 of the thickness of TWT within 24 hours after laying of stretch; otherwise indirect expenses could be increased. TWT. The joints are filled with a sealant material (Fig.  5). 1 3 245 Page 6 of 26 Innovative Infrastructure Solutions (2022) 7:245 Performance evaluation Pavement performance evaluation includes a range of quali- tative and quantitative measurements, intended to capture the structural and functional condition of pavements [14]. The information collected provides a ‘‘report card’’ of pave- ment condition at a particular point of time. Normally the collected pavement evaluation information is grouped into three broad categories, namely: (A) Serviceability (B) Structural capacity (C) Surface distress Serviceability The pavements are built for serving the traffic which repre- sents serviceability. This principle has motivated the use of a rating scale for pavement serviceability which ranges from 0 to 5. In which 0 signifies very poor and 5 signifies very good Fig. 6 FWD test rating. Serviceability of pavement is observed with rough- ness index. The roughness index test has been carried out on two constructed roads using axle mounted bump integrator. Structural capacity The capability of pavement to handle the traffic loads antici- pated over its life is known as structural capacity. There is a variety of commercially available devices for measuring in-situ pavement deflections, referred to as deflectometer. Deflectometer applies a known load to the surface and uses geophones arranged to yield a ‘‘bowl’’ of deflection meas- urements. These devices provide information not only on the structural capacity of pavement sections but also on the structural properties of their layers and the subgrade. The latter is done through back-calculation. Falling Weight Deflectometer (FWD) is used to assess the structural capac- ity of pavement [4] (Fig. 6). Response of pavement to falling Fig. 7 Rebound hammer test weight is recorded in terms of deflection and the structural capacity of pavement is worked out through back-calcula- tions. Program KUAB PVD software module is used to cal- Surface distress culate moduli and strain analysis with lifetime for required strength from respective input data. In-built calculations This component of performance evaluation involves the include calculations of modulus of elasticity for the lay- ers in a pavement, given the values for each layer thickness collection of data related to the condition of the pavement surface. Distresses are defined as the manifestations of con- and Poisson’s ratio. It uses an iterative procedure, where theoretical deflection values in a mathematical model are struction defects, as well as the damaging effects due to traf - fic, the environment, and their interactions. They encompass compared to the measured data, and the program adjusts the layer modulus until no further improvement is required. a broad variety of cracks and surface distortions. Data are typically collected manually through condition surveys. The The program then calculates the strains in the layers and works out which layer will fail first according to the strain variety of distresses encountered in concrete pavements is grouped into three main categories: cracking, surface criteria and predicts balance life. In situ strength of concrete pavement is assessed with the nondestructive testing method defects, and joint deficiencies. Joint deficiencies apply to jointed concrete pavements only. using a rebound hammer (Fig. 7). 1 3 Innovative Infrastructure Solutions (2022) 7:245 Page 7 of 26 245 (a) Cracking: Cracking appears in various forms that Wheel load allow identification of its causes. Some are fatigue-related, caused by the accumulation of fatigue damage from repeti- Heavy vehicles are not expected frequently on rural roads. tive vehicle axles, such as corner cracks. Other cracks, The maximum legal load limit on a single axle with dual either longitudinal or transverse, can be caused by traffic, wheels in India being 100 kN, the recommended design load the environment, or poor construction. The combination of on the dual wheel is 50 kN having a spacing of the wheels slab warping under thermal gradients and load may result in as 310 mm center to center. transverse cracks. Longitudinal and transverse crack severity is quantified as: Tyre pressure (i) Low: mean crack opening smaller than 3 mm. The tyre pressure is taken as 0.80 MPa for a truck carrying a (ii) Moderate: mean crack opening between 3 and 6 mm. dual wheel load of 50 kN. The effect of tyre pressure on the (iii) High: mean crack opening larger than 6 mm. wheel load stresses for the practical thickness of pavement is not significant. (b) Surface Defects Map cracking consists of intercon- nected cracks that extend only into the upper surface of the Design period and traffic growth rate slab. It may be caused by poor construction. Spalling is the result of the dislodgement of surface blocks created by map Concrete pavement for rural roads is designed for 20 years cracking. life. A traffic growth rate of 5% per year has been considered (c) Joint Deficiencies: Seals of transverse/longitudinal over the design period. joints can be damaged from a variety of causes, (e.g., split- ting or debonding due to age hardening) and result in mois- Subgrade strength ture and foreign object accumulation into the joint. Spalling is the breaking, chipping of slab edges within 0.6 m of trans- The strength of the subgrade is expressed in terms of the verse/longitudinal joints, and it is caused by either lack of modulus of subgrade reaction (k), which is determined by lateral support along a joint edge or by joints that do not carrying out a plate load test. Since subgrade strength is allow slab expansion due to the presence of foreign objects. affected by the moisture content, it is desirable to determine Performance evaluation of two constructed field stretches is it soon after the monsoon. Stresses in concrete pavement are done based on the above parameter (Table 3). not very sensitive to minor variation in k values and hence its value for a homogeneous soil subgrade may be obtained from its soaked CBR value. The minimum CBR of the sub- Design charts grade shall be 4%. The modulus of subgrade reaction for different subgrade CBR is given in Table  4. The Thin White Topping design charts are prepared for traf- fic less than 50 CVPD, 51 to 150. Cement treated base (CTB) CVPD, and less 450 CVPD with variable cement treated base thickness for different subgrade CBR values. The CTB material shall have a minimum unconfined com- The factors governing TWT pavement design are; pressive strength (UCS) of 4.5 to 7 MPa as per IRC: SP:89 Table 3 Performance evaluation of rigid pavement Sr. no. Name of road Length km Pavement composition Roughness index Structural capacity NDT Surface strength distress MPa 1 Sanaswadi To Dhanori 1.80 CTB-200 mm 2046 mm/km Good adequate 35 No TWT-200 mm Good 2 Pimpri To Ozare 0.50 CTB-200 mm 2100 mm/km Good adequate 30 No TWT-150 mm Good Table 4 Modulus of subgrade Soaked subgrade CBR 4 6 8 10 12 16 20 reaction(k) for different values of subgrade CBR k value (MPa/m) 35 42 49 54 59 65 68 1 3 245 Page 8 of 26 Innovative Infrastructure Solutions (2022) 7:245 [15] in 7/28 days curing. The strength of cementitious lay- the composite k value of pavement is improved and it is ers keeps on rising with time and an elastic modulus of considered in the design, based on subgrade CBR and CTB 5000  MPa can be considered for analysis of pavements thickness. The composite k value is given in Table 5. The with CTB layers having 7/28-day unconfined compression relation between composite k value and CTB thickness for strength values ranging between 4.5 and 7 MPa. The conven- different subgrade CBR(%) is shown in Fig.  8. tional cement treated layer should attain the above strength in 7 days, whereas lime and lime fly ash stabilized granular Concrete strength materials and soils should achieve the strength in 28 days since the strength gain rate is slow in such materials. Curing Since concrete pavements fail due to bending stresses, their of cemented bases shall be done for a minimum period of design must be based on flexural strength of concrete. The seven days before the commencement of the construction following relationship is used to determine flexural strength. of the next upper layer for achieving the required strength. √ f = 0.7 f (3) f ck Poisson’s ratio value of CTB material can be taken as 0.25. While preparing design charts for TWT the thickness of where CTB varying from 100 to 300 mm has been considered. The f = flexural strength in MPa. design of rigid pavement is based on modulus of subgrade f = characteristic compressive cube strength in MPa. ck reaction (k). Due to the provision of CTB over subgrade, Table 5 Composite modulus of CTB thickness CBR (%) subgrade reaction(k) in MPa/m in mm for different subgrade CBR and 4 6 8 10 12 16 20 CTB thickness 100 105.5 134.7 160.3 183.4 204.7 243.5 278.6 150 134.1 168.8 198.7 225.5 250.1 294.3 334 200 163.1 203.1 237.3 267.8 295.5 345.3 389.6 250 192.5 237.8 276.3 310.3 341.2 396.4 445.2 300 222.5 273 315.7 353.3 387.3 447.8 501.2 Fig. 8 Composite k value in MPa/m for different CBR(%) and CTB Thickness 1 3 Innovative Infrastructure Solutions (2022) 7:245 Page 9 of 26 245 For low volume roads, it is suggested that the 90 days strength may be used for design since concrete keeps on gaining strength with time. The 90-days flexural strength may be taken as 1.10 times the 28-day flexural strength as per IRC SP 62–2014. Minimum M30 grade concrete should be used for pavement construction of rural roads, Modulus of elasticity and Poisson’s Ratio The modulus of Elasticity E of concrete and Poisson’s ratio is taken as 30,000 MPa and 0.15, respectively. Coefficient of thermal expansion The coefficient of thermal expansion of concrete α is taken as; −6 α = 10 × 10 per °C. Fatigue behaviour of concrete pavement For most rural roads, fatigue behaviour is not so important because of a low volume of commercial vehicles. For rural road fatigue criteria with 60% reliability is used considering 40% cracking of slab at the end of design life. −2.222 SR Log N = (4) 10 f 0.523 N = Fatigue life of a pavement subjected to stresses caused by the combined effect of wheel load of 50 kN and temperature gradient. SR = Stress Ratio = Flexural stress due to wheel load and temperature Flexural strength Critical stress condition Concrete pavements are subjected to stresses due to a vari- ety of factors and the conditions which induce the highest stress in the pavement should be considered for analysis. The factors commonly considered for the design of pavement thickness are traffic loads and temperature gradients. The effects of moisture changes and shrinkage are of a smaller magnitude, and they are neglected in thickness design. The effect of the temperature gradient is very less at the corner, while it is much higher at the edge. Concrete pavements undergo daily cyclic changes of temperature differentials, the top being hotter than the bottom during the daytime and the opposite is the case during the nighttime. The conse- quent tendency of pavement slabs to curl upwards during the daytime and downwards during the nighttime and restraint offered to curling by the self-weight of pavement induces 1 3 Table 6 Thin white topping thickness for traffic less than 50 CVPD and concrete grade M30/M35/M40 CTB thick- Subgrade CBR (%) ness mm 4 6 8 10 12 16 20 Grade M30 M35 M40 M30 M35 M40 M30 M35 M40 M30 M35 M40 M30 M35 M40 M30 M35 M40 M30 M35 M40 100 140 130 125 135 130 120 130 125 120 130 120 115 125 120 115 125 115 110 120 115 110 150 135 130 120 130 125 120 125 120 115 125 120 110 125 115 110 120 110 105 115 110 105 200 130 125 120 125 120 115 125 115 110 120 115 110 120 110 105 115 110 105 115 105 100 250 130 120 115 125 115 110 120 115 110 120 110 105 115 110 105 110 105 100 110 100 95 300 125 120 110 120 115 110 120 110 105 115 110 100 115 105 100 110 100 95 105 100 95 245 Page 10 of 26 Innovative Infrastructure Solutions (2022) 7:245 Fig. 9 Thin White Topping thickness for traffic < 50 CVPD and Concrete Grade M30 Fig. 10 Thin White Topping thickness for traffic < 50 CVPD and Concrete Grade M35 1 3 Innovative Infrastructure Solutions (2022) 7:245 Page 11 of 26 245 Fig. 11 Thin White Topping thickness for traffic < 50 CVPD and Concrete Grade M40 stresses in the pavement referred to commonly curling a: radius of the equivalent circular area and it is calcu- stresses. These stresses are flexural, being tensile at the bot- lated by Eqs. (7) and (8), tom during the daytime and at the top during the nighttime. Corners have very little restraint and temperature stresses a = for single Wheel (7) in the corner region are negligible. Hence, edge stress is considered critical for the design of pavement thickness. For Thin White Topping with shorter joint spacing, top-down 0.8521P S P cracking will not take place as both wheels of the vehicle are d d d (8) a = + for dual Wheel not placed on the same panel. The maximum tensile stresses p  0.5227p in the edge region will be critical during the daytime. S : Spacing between the center of duel wheel. A. Wheel load stress at the edge is calculated using the d P : Load on one wheel. Westergaard Eq. (5). d P—Tyre pressure. 3(1 + )P Temperature stress ( σ ) te (3 + )h Bradbury’s equation is used for the computation of tem- 4 1 −  1.18(1 + 2)a perature stress. The temperature gradient across the depth Eh ln + 1.84 − + + is usually nonlinear. The compressive stress due to bi-linear 3 2 l 100ka temperature variation is subtracted. Temperature stress is (5) calculated by equation (9), σ : edge stress in MPa. h: Pavement thickness in mm. 0.67 × C ×  ×ΔT × E E ×  ×ΔT = − (9) te k: Modulus of subgrade reaction MPa/m. 2 3 × 3.91 P: Single Wheel Load, N σ : temperature stress in MPa. μ: Poisson’s ratio for concrete. te C: Correction factor. E: Modulus of elasticity of concrete in MPa. α: coefficient of thermal expansion. l: radius of relative stiffness and calculated by Eq. (6 ), 3 4 Eh (6) l = 12(1 −  )k 1 3 245 Page 12 of 26 Innovative Infrastructure Solutions (2022) 7:245 1 3 Table 7 Thin white topping thickness for traffic 51 to 150 CVPD and concrete grade M30 CTB Joint Subgrade CBR (%) thick- spac- CBR 4% CBR 6% CBR 8% CBR 10% CBR 12% CBR 16% CBR 20% ness ing m mm Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone I II, IV, III I II, IV, II I II,IV, III I II,IV, III I II,IV, III I II,IV, III I II,IV, III V, VI V, VI V,VI V,VI V,VI V,VI V,VI 100 1.5 140 140 140 135 135 135 135 135 135 130 130 135 130 130 130 130 130 130 125 130 130 2.0 145 145 145 145 145 145 140 145 145 140 140 145 140 145 145 140 140 145 135 140 145 2.5 155 155 160 150 155 155 150 155 155 145 150 155 150 155 155 145 150 155 145 150 155 150 1.5 135 135 135 135 135 135 130 130 130 130 130 130 130 130 130 125 130 130 125 130 130 2.0 145 145 145 140 145 145 140 145 145 140 140 145 140 140 145 135 140 145 135 140 140 2.5 150 155 155 150 155 155 150 155 155 145 150 155 145 150 155 145 150 155 140 150 155 200 1.5 135 135 135 130 130 130 130 130 130 130 130 130 125 130 130 125 125 130 125 125 125 2.0 140 145 145 140 145 145 140 140 145 140 140 145 135 140 140 135 140 140 135 140 140 2.5 150 155 155 150 155 155 145 150 155 145 150 155 145 150 155 140 150 150 140 145 150 250 1.5 130 130 130 130 130 130 125 130 130 125 130 130 125 125 130 125 125 125 120 125 125 2.0 140 145 145 140 140 145 135 140 145 135 140 140 135 140 140 135 140 140 130 135 140 2.5 150 155 155 145 150 155 145 150 155 145 150 155 140 150 150 140 145 150 135 145 150 300 1.5 130 130 130 125 130 130 125 125 130 125 125 130 125 125 125 120 125 125 120 125 125 2.0 140 140 145 135 140 145 135 140 140 135 140 140 135 140 140 130 135 140 130 135 140 2.5 145 150 155 145 150 155 140 150 155 140 150 150 140 145 150 135 145 150 135 140 145 Innovative Infrastructure Solutions (2022) 7:245 Page 13 of 26 245 1 3 Table 8 Thin white topping thickness for traffic 51 to 150 CVPD and concrete grade M35 CTB Joint Subgrade CBR (%) thick- spac- CBR 4% CBR 6% CBR 8% CBR 10% CBR 12% CBR 16% CBR 20% ness ing m mm Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone I II,IV, III I II,IV, III I II,IV, III I II,IV, III I II,IV, III I II,IV, III I II,IV, III V,VI V,VI V,VI V,VI V,VI V,VI V,VI 100 1.5 130 130 130 130 130 130 125 130 130 125 125 125 125 125 125 120 125 125 120 120 125 2.0 140 140 140 135 140 140 135 135 140 135 135 140 135 135 135 130 135 135 130 135 135 2.5 145 150 150 145 145 150 145 145 150 140 145 145 140 145 145 135 145 145 135 140 145 150 1.5 130 130 130 125 125 125 125 125 125 125 125 125 120 125 125 120 120 125 120 120 120 2.0 135 140 140 135 135 140 135 135 135 130 135 135 130 135 135 130 135 135 125 130 135 2.5 145 145 150 140 145 150 140 145 145 140 145 145 135 140 145 135 140 145 130 140 140 200 1.5 125 125 130 125 125 125 120 125 125 120 125 125 120 120 125 120 120 120 115 120 120 2.0 135 135 140 135 135 135 130 135 135 130 135 135 130 135 135 125 130 135 125 130 130 2.5 140 145 150 140 145 145 140 145 145 135 140 145 135 140 145 130 140 140 130 135 140 250 1.5 125 125 125 120 125 125 120 120 125 120 120 120 120 120 120 115 120 120 115 120 120 2.0 135 135 135 130 135 135 130 135 135 130 130 135 125 130 135 125 130 130 125 130 130 2.5 140 145 145 135 145 145 135 140 145 135 140 145 130 140 140 130 135 140 125 135 135 300 1.5 125 125 125 120 120 125 120 120 120 120 120 120 115 120 120 115 120 120 115 115 120 2.0 130 135 135 130 135 135 130 130 135 125 130 135 125 130 130 125 130 130 120 125 130 2.5 140 145 145 135 140 145 135 140 145 135 140 140 130 135 140 125 135 135 125 130 135 245 Page 14 of 26 Innovative Infrastructure Solutions (2022) 7:245 1 3 Table 9 Thin white topping thickness for traffic 51 to 150 CVPD and concrete grade M40 CTB Joint Subgrade CBR (%) thick- spac- CBR 4% CBR 6% CBR 8% CBR 10% CBR 12% CBR 16% CBR 20% ness ing m mm Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone I II,IV, III I II,IV, III I II,IV, III I II,IV, III I II,IV, III I II,IV, III I II,IV, III V,VI V,VI V,VI V,VI V,VI V,VI V,VI 100 1.5 125 125 125 125 125 125 120 120 120 120 120 120 120 120 120 115 120 120 115 115 120 2.0 130 135 135 130 135 135 130 130 135 130 130 130 125 130 130 125 130 130 125 125 130 2.5 140 140 145 135 140 140 135 140 140 135 140 140 130 135 140 130 135 140 130 135 135 150 1.5 125 125 125 120 120 120 120 120 120 120 120 120 115 120 120 115 115 120 115 115 115 2.0 130 135 135 130 130 130 125 130 130 125 130 130 125 130 130 120 125 130 120 125 125 2.5 135 140 140 135 140 140 135 140 140 130 135 140 130 135 135 125 135 135 125 130 135 200 1.5 120 120 120 120 120 120 115 120 120 115 120 120 115 115 115 115 115 115 110 115 115 2.0 130 130 130 125 130 130 125 130 130 125 125 130 120 125 130 120 125 125 120 125 125 2.5 135 140 140 130 136 140 130 135 135 130 135 135 125 135 135 125 130 135 120 130 130 250 1.5 120 120 120 115 120 120 115 115 120 115 115 115 115 115 115 110 115 115 110 110 115 2.0 125 130 130 125 130 130 125 125 130 120 125 125 120 125 125 120 125 125 115 120 125 2.5 135 140 140 130 135 140 130 135 135 125 130 135 125 130 135 120 125 130 120 125 130 300 1.5 120 120 120 115 120 120 115 115 115 115 115 115 110 115 115 110 110 115 110 110 110 2.0 125 130 130 125 125 130 120 125 125 120 125 125 120 125 125 115 120 125 115 120 120 2.5 130 135 140 130 135 135 125 130 135 125 130 130 120 130 130 120 125 130 115 125 125 Innovative Infrastructure Solutions (2022) 7:245 Page 15 of 26 245 Fig. 12 Thin White Topping thickness for traffic 51 to 150 CVPD, Concrete Grade M30 and Subgrade CBR 4% Fig. 13 Thin White Topping thickness for traffic 51 to 150 CVPD, Concrete Grade M30, and Subgrade CBR 6% 1 3 245 Page 16 of 26 Innovative Infrastructure Solutions (2022) 7:245 Fig. 14 Thin White Topping thickness for traffic 51 to 150 CVPD, Concrete Grade M30 and Subgrade CBR 8% Fig. 15 Thin White Topping thickness for traffic 51 to 150 CVPD, Concrete Grade M30 and Subgrade CBR 10% 1 3 Innovative Infrastructure Solutions (2022) 7:245 Page 17 of 26 245 Fig. 16 Thin White Topping thickness for traffic 51 to 150 CVPD, Concrete Grade M30 and Subgrade CBR 12% Fig. 17 Thin White Topping thickness for traffic 51 to 150 CVPD, Concrete Grade M30 and Sibgrade CBR 16% 1 3 245 Page 18 of 26 Innovative Infrastructure Solutions (2022) 7:245 Fig. 18 Thin White Topping thickness for traffic 51 to 150 CVPD, Concrete Grade M30 and Subgrade CBR 20% ΔT: temperature differential °C. thickness design chart for M30, M35, and M40 con- Temperature differentials in different zones in India are crete grades is given in Table 6. As temperature stresses taken as recommended by Central Road Research Institute are not considered in the design, spacing of joint and Table 4.1 of IRC SP 62-2014 [11]. For Thin white topping, temperature zone does not have effect on thickness the concrete thickness is less than 200 mm hence tempera- of TWT. Preferably joint spacing should be provided ture differential values in zone II, IV, V, VI are nearly the 12 to 15 times the thickness of TWT. For a particular same and hence clubbed in single group. subgrade CBR value, the TWT thickness requirement decreases with increase in CTB thickness up to certain Joint spacing extent. Also for a particular CTB thickness, the TWT thickness requirement decreases with increase in sub- The Joint spacing for concrete pavement is recommended 12 grade CBR value. Effect of CTB thickness on TWT to 15 times the thickness of concrete. From the construction thickness for concrete grade M30, M35 and M40 is point of view, joint spacing of 1.5-m, 2.0 m, and 3.00 m has shown in Figures 9, 10, 11. been considered in the design. (b) Traffic 51 to 150 CVPD: For traffic higher than 50 and less than 150 CVPD, Pavement design charts the thickness evaluation should be done based on total stresses resulting from wheel load of 50 kN and tem- Pavement design charts are prepared considering traffic, perature differential. The TWT thickness design charts Subgrade CBR, CTB thickness, grade of concrete, and trans- for M30, M35, and M40 concrete grades are given in verse joint spacing. Tables 7, 8, 9. As temperature stresses are considered in the design, joint spacing and temperature zone has (a) Traffic less than 50 CVPD: effect on thickness requirement of TWT. For a par - For traffic, less than 50 CVPD only wheel load ticular subgrade CBR value and CTB thickness, the stresses for a load of 50 kN on dual wheel need be TWT thickness requirement increases with increase in considered for thickness estimation since there is a low joint spacing. TWT thickness requirement for zone III probability of maximum wheel load and highest tem- is higher and lower for zone I. For lower joint spacing perature differential between the top and bottom of the effect of zone is insignificant. The effect of CTB thick - rigid pavement occurring at the same time. The TWT ness on TWT thickness for different temperature zones 1 3 Innovative Infrastructure Solutions (2022) 7:245 Page 19 of 26 245 1 3 Table 10 Thin white topping thickness for traffic < 450 CVPD and concrete grade M30 CTB Joint Subgrade CBR (%) thick- spac- CBR 4% CBR 6% CBR 8% CBR 10% CBR 12% CBR 16% CBR 20% ness ing m mm Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone I II,IV, III I II,IV,V,VI III I II,IV, III I II,IV,V,VI III I II,IV, III I II,IV, III I II,IV, III V,VI V,VI V,VI V,VI V,VI 100 1.5 185 185 185 185 185 185 180 180 180 180 180 180 175 175 175 175 175 175 175 175 175 2.0 195 195 195 190 190 190 190 190 190 190 190 190 190 190 190 190 190 190 190 190 195 2.5 205 205 205 205 205 210 205 205 210 205 210 210 205 210 215 205 210 215 205 215 220 150 1.5 185 185 185 180 180 180 175 175 175 175 175 175 175 175 175 175 175 175 170 170 175 2.0 190 190 190 190 190 190 190 190 190 190 190 190 190 190 190 190 190 195 190 190 195 2.5 205 205 205 205 205 210 205 210 215 205 210 215 205 210 215 205 215 220 205 215 220 200 1.5 180 180 180 175 175 175 175 175 175 175 175 175 175 175 175 170 170 170 170 170 170 2.0 190 190 190 190 190 190 190 190 190 190 190 195 190 190 195 190 190 195 190 195 195 2.5 205 205 210 205 210 210 205 210 215 205 210 215 205 215 220 205 215 220 205 215 225 250 1.5 180 180 180 175 175 175 175 175 175 170 175 175 170 170 170 170 170 170 170 170 170 2.0 190 190 190 190 190 190 190 190 195 190 190 195 190 190 195 190 195 195 190 195 200 2.5 205 210 210 205 210 210 205 215 220 205 215 220 205 215 220 205 215 225 205 215 225 300 1.5 175 175 175 175 175 175 170 175 175 170 170 170 170 170 170 170 170 170 170 170 170 2.0 190 190 190 190 190 195 190 190 195 190 190 195 190 195 195 190 195 200 190 195 200 2.5 205 210 215 205 215 215 205 215 220 205 215 220 205 215 225 205 215 225 205 220 230 245 Page 20 of 26 Innovative Infrastructure Solutions (2022) 7:245 1 3 Table 11 Thin white topping thickness for traffic < 450 CVPD and concrete grade M35 CTB Joint Subgrade CBR (%) thick- spac- CBR 4% CBR 6% CBR 8% CBR 10% CBR 12% CBR 16% CBR 20% ness ing m mm Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone I II,IV, III I II,IV, III I II,IV, III I II,IV, III I II,IV, III I II,IV, III I II,IV, III V,VI V,VI V,VI V,VI V,VI V,VI V,VI 100 1.5 180 180 180 175 175 175 170 170 170 170 170 170 170 170 170 165 165 165 165 165 165 2.0 185 185 185 185 185 185 180 185 185 180 185 185 180 185 185 180 180 185 180 185 185 2.5 195 195 200 195 200 200 195 200 200 195 200 205 195 200 205 195 200 205 195 205 210 150 1.5 175 175 175 170 170 170 170 170 170 170 170 170 165 165 165 165 165 165 165 165 165 2.0 185 185 185 180 185 185 180 185 185 180 180 185 180 180 185 180 185 185 180 185 185 2.5 195 200 200 195 200 200 195 200 205 195 200 205 195 200 205 195 205 210 195 205 210 200 1.5 170 170 170 170 170 170 165 165 165 165 165 165 165 165 165 165 165 165 160 165 165 2.0 180 185 185 180 185 185 180 180 185 180 185 185 180 185 185 180 185 185 180 185 190 2.5 195 200 200 195 200 205 195 200 205 195 205 210 195 205 210 195 205 210 195 205 210 250 1.5 170 170 170 165 165 165 165 165 165 165 165 165 165 165 165 160 165 165 160 165 165 2.0 180 185 185 180 180 185 180 185 185 180 185 185 180 185 185 180 185 190 180 185 190 2.5 195 200 205 195 200 205 195 205 210 195 205 210 195 205 210 195 205 210 195 205 215 300 1.5 170 170 170 165 165 165 165 165 165 165 165 165 160 165 165 160 165 165 160 160 165 2.0 180 180 185 180 185 185 180 185 185 180 185 185 180 185 190 180 185 190 180 185 190 2.5 195 200 205 195 205 210 195 205 210 195 205 210 195 205 210 195 205 215 195 205 215 Innovative Infrastructure Solutions (2022) 7:245 Page 21 of 26 245 1 3 Table 12 Thin white topping thickness for traffic < 450 CVPD and concrete grade M40 CTB Joint Subgrade CBR (%) thick- spac- CBR 4% CBR 6% CBR 8% CBR 10% CBR 12% CBR 16% CBR 20% ness ing m mm Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone I II,IV, III I II,IV, III I II,IV, III I II,IV, III I II,IV, III I II,IV, III I II,IV, III V,VI V,VI V,VI V,VI V,VI V,VI V,VI 100 1.5 170 170 170 170 170 170 165 165 165 165 165 165 165 165 165 160 160 160 160 160 160 2.0 180 180 180 175 175 180 175 175 175 175 175 175 175 175 175 175 175 180 175 175 180 2.5 190 190 190 190 190 195 190 190 195 190 195 195 190 195 195 190 195 200 185 195 200 150 1.5 170 170 170 165 165 165 165 165 165 160 160 160 160 160 160 160 160 160 155 160 160 2.0 175 175 180 175 175 175 175 175 175 175 175 175 175 175 180 175 175 180 175 175 180 2.5 190 190 195 190 195 195 190 195 195 190 195 200 190 195 200 185 195 200 185 195 200 200 1.5 165 165 165 165 165 165 160 160 160 160 160 160 160 160 160 155 160 160 155 155 160 2.0 175 175 175 175 175 175 175 175 175 175 175 180 175 175 180 175 175 180 170 175 180 2.5 190 195 195 190 195 195 190 195 200 185 195 200 185 195 200 185 195 200 185 195 205 250 1.5 165 165 165 160 160 160 160 160 160 160 160 160 155 160 160 155 155 160 155 155 155 2.0 175 175 175 175 175 175 175 175 180 175 175 180 175 175 180 170 175 180 170 175 180 2.5 190 195 195 190 195 200 185 195 200 185 195 200 185 195 200 185 195 205 185 195 205 300 1.5 160 160 160 160 160 160 160 160 160 155 160 160 155 155 160 155 155 155 155 155 155 2.0 175 175 175 175 175 180 175 175 180 170 175 180 170 175 180 170 175 180 170 175 180 2.5 190 195 200 185 195 200 185 195 200 185 195 200 185 195 205 185 195 205 185 195 205 245 Page 22 of 26 Innovative Infrastructure Solutions (2022) 7:245 Fig. 19 Thin White Topping thickness for traffic < 450 CVPD, Concrete Grade M30 and Subgrade CBR 4% Fig. 20 Thin White Topping thickness for traffic < 450 CVPD, Concrete Grade M30 and Subgrade CBR 6% and joint spacing for M30 grade concrete and different (c) Traffic less than 450 CVPD: subgrade CBR is shown in Figures 12, 13, 14, 15, 16, 17, 18. 1 3 Innovative Infrastructure Solutions (2022) 7:245 Page 23 of 26 245 Fig. 21 Thin White Topping thickness for traffic < 450 CVPD, Concrete Grade M30 and Subgrade CBR 8% Fig. 22 Thin White Topping thickness for traffic < 450 CVPD, Concrete Grade M30 and Subgrade CBR 10% For traffic exceeding 150 CVPD, fatigue can be a real thickness is designed considering combined stresses due problem, and thickness evaluation based on fatigue frac- to wheel load edge stress for the dual wheel of 50 kN and ture with 60% reliability should be considered. Pavement temperature gradient. Also, concrete pavement is checked 1 3 245 Page 24 of 26 Innovative Infrastructure Solutions (2022) 7:245 Fig. 23 Thin White Topping thickness for traffic < 450 CVPD, Concrete Grade M30 and Subgrade CBR 12% Fig. 24 Thin White Topping thickness for traffic < 450 CVPD, Concrete Grade M30 and Subgrade CBR 16% for fatigue criteria. Assuming 10% of total traffic is having number of repetitions is computed considering 60% reliabil- an axle load of more than 100 kN, the expected number of ity from the fatigue equation. Cumulative fatigue damage is vehicles is computed over the design period. The allowable computed and it should be less than 1. The TWT thickness 1 3 Innovative Infrastructure Solutions (2022) 7:245 Page 25 of 26 245 Fig. 25 Thin White Topping thickness for traffic < 450 CVPD, Concrete Grade M30 and Subgrade CBR 20% charts for concrete grades M30, M35, and M40 are given in subgrade CBR for rural roads. From the development of Tables 10,11,12. The TWT thickness requirement increases design charts following are the significant observations, with increase in joint spacing. The effect of zone is insig- nificant keeping all other parameters constant. TWT thick - Composite modulus of subgrade reaction (k) value ness requirement decreases with increase in CTB thickness increases with an increase in thickness of CTB. for 1.5 meter joint spacing The TWT thickness requirement The optimum thickness of TWT can be obtained from decreses with increase in subgrade CBR value upto certain Design Chart and the economy in the Pavement design extent for same CTB thickness and joint spacing. The effect can be achieved. of CTB thickness on TWT thickness for different tempera- • For low CBR Subgrade value, increase in CTB thickness ture zones and joint spacing for M30 grade concrete and can reduce TWT Thickness only up to the certain extent different subgrade CBR is shown in Figures 19, 20, 21, 22, • For an increase in Joint spacing the required TWT thick- 23, 24, 25. ness increases. • For Joint spacing of 1.5 m, TWT thickness is the same for all zones. Conclusions • For Joint spacing 2.0  m and 2.5-m, TWT thickness requirement is higher for Zone III and lower for Zone I. The design charts for Thin White Topping with variable thickness of cement treated base and different subgrade CBR The Thin White Topping pavement structures over ade- are prepared for rural roads. With Cold In Place Recycling quate base support would have superior load carrying capa- technique, existing local material can be utilized and the bility hence Thin White Topping pavement structure rec- strength of subgrade and subbase shall be improved with ommended as a pavement design alternative in low-volume cement stabilization. From field experiments the perfor - rural roads. The construction of rural roads with CTB using mance evaluation rating after two years of construction is the CIPR technique is an effective and environmentally good for pavement constructed with CTB using CIPR tech- friendly solution. nique and Thin White Topping. Surface cracking, potholes, Acknowledgements I am thankful to Rural Development Department, rutting, or any defects are not observed. Thin White Topping Government of Maharashtra for sanctioning the road works in Mukhya thickness design charts of M30, M35 and M40 are developed Mantri Gram Sadak Yojana under research and development scheme. for varying thickness of cement treated base and different 1 3 245 Page 26 of 26 Innovative Infrastructure Solutions (2022) 7:245 Authors' contribution Designed and developed the methodology 2. Ramachandra V (2011) White topping: an excellent solution for for the construction of rural roads with Cement Treated Base. Trial pavement rehabilitation NBM & CW stretches are constructed using cement treated base with Cold In Place 3. Kadiyali LR and Associates (2010) Handbook on Cement Con- Recycling technology. Performance evaluation of these roads has been crete Roads Cement Manufacturer’s Association, New Delhi carried out after two years of construction. Thin White Topping thick- 4. Skanda Kumar BN, Suhas R, Bhavan V (2014) Performance ness design charts with variable cement treated base thickness for dif- evaluation of thin white topping. Int J Res Eng Technol. https:// ferent subgrade CBR values and Traffic are prepared for rural roads. doi. org/ 10. 15623/ ijret. 2014. 03070 68 These charts are useful for construction of rural roads to the Field 5. Li Z, Vandenbossch JM (2013) Redefining the failure mode for Engineers. thin and ultra-thin white topping with a 1.8 x 1.8 m (6 x 6-ft) joint spacing. Transp Res Board Pittsburgh. https:// doi. org/ 10. 3141/ 2368- 13 Funding The construction of trial roads is sanctioned in Mukhya Man- 6. Bagui SK (2012) Pavement design for rural low volume roads tri Gram Sadak Yojana Research and Development Scheme by the using cement and lime treatment base. Jorden J Civil Eng Government of Maharashtra. The construction cost of two roads is as 6:293–303 below, Construction of Sanaswadi to Dhanore Road Taluka: Shirur 7. Kumar S, Sahu A, Naval S (2020) Influence of jute fibre on CBR Dist: Pune Cost: Rs. 472.73 lakhs. Construction of Pimpre to Ozare value of expansive soil. Civil Eng J. https://doi. or g/10. 28991/ cej- Road Taluka: Indapur Dist: Pune Cost: Rs. 270.83 lakhs. 2020- 03091 539 8. Erdawaty, Harianto T, Muhiddin AB, Arsyad A (2020) Experi- Declarations mental study on bearing capacity of alkaline activated granular asphalt concrete columns on soft soils. Civil Eng J. https://doi. or g/ Conflict of interest On behalf of all authors, the corresponding author 10. 28991/ cej- 2020- 03091 623 states that there is no conflict of interest. 9. IRC: 37-2018, “Guidelines For Design of Flexible Pavements” (Fourth Revision), Indian Road Congress Data availability Some or all data, models, or code that support the 10. IRC: 58-2015, “Guidelines for The Design Of Plain Jointed findings of this study are available from the corresponding author upon Rigid Pavements For Highways”, (Fourth Revision) Indian Road reasonable request. Congress 11. IRC SP 62-2014: “Guidelines for Design and Construction of Cement Concrete Pavements for Low Volume Roads”, Indian Open Access This article is licensed under a Creative Commons Attri- Road Congress bution 4.0 International License, which permits use, sharing, adapta- 12. Harrington D, Snyder & Associates, Inc.Gary Fick, Trinity Con- tion, distribution and reproduction in any medium or format, as long struction Management Services, Inc., (2014) Guide to Concrete as you give appropriate credit to the original author(s) and the source, Overlays Sustainable Solutions for Resurfacing and Rehabilitating provide a link to the Creative Commons licence, and indicate if changes Existing Pavements” American Concrete Pavement Association. were made. The images or other third party material in this article are https:// doi. org/ 10. 13140/ RG.2. 1. 3106. 4724 included in the article's Creative Commons licence, unless indicated 13. IRC: SP: 76-2015, “Guidelines For Conventional and Thin White otherwise in a credit line to the material. If material is not included in Topping” ( First Revision), Indian Road Congress the article's Creative Commons licence and your intended use is not 14. Delatte N (2008) Concrete pavement design construction and per- permitted by statutory regulation or exceeds the permitted use, you will formance. Taylor & Francis, London, New York need to obtain permission directly from the copyright holder. To view a 15. IRC:SP:89-2018 (Part II), "Guidelines for the Design of Stabilised copy of this licence, visit http://cr eativ ecommons. or g/licen ses/ b y/4.0/ . Pavements (Part II)," Indian Roads Congress References 1. Wu Z, Rupnow T, Mahdi MI (2017) Roller compacted concrete over soil cement under accelerated loading, Louisiana Transp Res Center LA. https:// doi. org/ 10. 1061/ 97807 84479 216. 038 1 3 http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Innovative Infrastructure Solutions Springer Journals

Design and development of methodology for construction of thin white topping for rural roads in India

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2364-4176
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10.1007/s41062-022-00762-7
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Abstract

A large proportion of villages in India have been connected with water bound macadam (WBM) or bituminous roads. Rural roads usually have a low volume of traffic, consisting mostly of light transport vehicles with less frequency of heavy traffic. Maintenance of these roads is neglected because of the paucity of funds and the created road asset is in deteriorated condi- tion. The non-availability of suitable soil and aggregates has made projects unviable and cost prohibitive. This aggregate scarcity will increase further as a result of environmental conservation and restriction on mining. There is a need to develop alternative pavement designs to construct sustainable and durable rural roads. The stabilization of soil/aggregate is being used worldwide towards optimal usage of scarce resources. The concepts of soil/aggregate stabilization and Cold In Place Recycling technique provide a comprehensive solution for rehabilitation of existing road and greenfield road construction. Cold In Place Recycling process allows usage of locally available marginal materials. The stabilization process can use a wide range of stabilization agents such as soil-aggregate mix, lime, cement, fly ash, foamed bitumen, emulsion, polymers, and other proprietary chemical stabilizers. Two rural roads are identified under Mukhya Mantri Gram Sadak Yojana Research and Development Scheme. Pavements are designed considering cement treated base. These roads are constructed using the Cold In Place Recycling technique. The existing water bound macadam (WBM)/deteriorated bituminous surface is stabilized with cement. Bituminous concrete and Thin White Topping are provided as wearing course. The performance of pavement is evaluated after 2 years of construction. Also, the balance life of the pavement is checked and the results are satisfactory. The stabilized pavements offer superior strength and longevity, even in extreme climatic conditions, and provide better per - formance. The design charts for Thin White Topping for rural roads are not available, hence the design charts for Thin White Topping of M30/M35/M40 grade concrete on Cement Treated Base of varying thickness and different subgrade CBR are prepared based on IRC 62-2014 for traffic less than 50 CVPD, 51 to 150 CVPD, and less than 450 CVPD. These charts are ready to use and act as a guide to the Field Engineers. The optimum thickness of Thin White Topping can be selected from the chart for known subgrade CBR and Traffic. The effect of variation of CTB thickness on Thin White Topping thickness can be determined from the chart. Keywords Cement treated base (CTB) · Thin white topping (TWT) · Cold in place recycling (CIPR) · Rural roads · Stabilization · California bearing ratio (CBR) Introduction A large proportion of villages in India have been connected with water bound macadam (WBM) or bituminous roads. Rural roads usually have a low volume of traffic, consist- ing mostly of light transport vehicles with less frequency * R. Y. Patil of heavy traffic. Mostly flexible pavements with granular patilry.civil@coep.ac.in subbase and base having thin bituminous carpet as wearing M. S. Ranadive course are adopted in rural roads, which deteriorate dur- msr.civil@coep.ac.in ing monsoon seasons leading to costly maintenance every Civil Engineering Department, College of Engineering Pune, year. Maintenance of these roads is neglected because of the Pune, Maharshtra, India Vol.:(0123456789) 1 3 245 Page 2 of 26 Innovative Infrastructure Solutions (2022) 7:245 paucity of funds and the created road asset is in deteriorated Thin White Topping for rural roads are not available. The condition. The non-availability of suitable soil and aggre- goal of present research is to design and develop methodol- gates has made projects unviable and cost prohibitive. This ogy for construction of Thin White Topping for rural roads. has necessitated the exploration of other alternative pave- The development of these charts can be useful for Field ments. The stabilization of existing local available material Engineers. Thin White Topping design charts with variable provides an effective solution. Wu et al.[1 ] constructed six thickness of cement treated base and different subgrade CBR full scale accelerated pavement testing tracks with cement are developed for rural roads. treated base with thin white topping and after testing in laboratory concluded that, the Roller Compacted Concrete pavement structures over adequate base support would have Cement treated base with cold in place superior load carrying capability hence thin RCC-surfaced recycling technique pavement structure recommended as a pavement design alternative in low-volume pavement design. Ramachandra, Quality road aggregates have become rare and costly in [2] studied a technology demonstration project in Banglore many places in India due to the massive construction activi- to demonstrate the advantages of white topping by making ties required for the development of new infrastructure use of the advances in construction equipment and methods facilities. It is a need to look for ways of improving lower and concluded that concrete roads and white topping provide quality materials that are readily available for use in road- a sustainable as well as cost-effective option for pavement way construction. Cement/ lime treatment has become an construction. The guidelines for construction of cement con- accepted method for increasing the strength and durability crete roads are presented by. Kadiyalie [3] which includes of soils and marginal aggregates. Soil cement is a highly advantages and disadvantages of concrete roads, techno- compacted mixture of soil/aggregate, cement, and water. The economic aspects, properties and testing of concrete, design advantages of the soil–cement mixture are great strength and mixes, drainage considerations, specifications for subgrade, durability combined with low first cost. subbase, concrete pavement design, joints, quality control, Advantages of Cement stabilization are— a special technique of concrete paving, and use of fly ash in concrete roads. Skanda Kumar et al. [4] conducted perfor- • Cement is easily available mance evaluation studies to determine the functional and Cost is relatively low structural condition of a white topping overlay. Li and Van- • Highly durable denbossch [5] developed three dimensional finite-element Weather resistant and strong model for thin white topping subjected to environmental • Reduces swelling characteristics of the soil and wheel loads and concluded that the maximum tensile stress is induced in the wheel path and at the bottom of the Many existing rural roads in India are unpaved low vol- PCC overlay, which results in a longitudinal crack. S K ume roads. Heavy rainfall and floods affect almost all these Bagui [6] developed design curves to estimate thickness of roads frequently. The roads are severely damaged due to soil–cement base and that of the soil–lime subbase for dif- floods, currents, and wave action. This situation requires ferent traffic and different values of modulus of soil–cement the maintenance of these roads frequently. These adverse and soil–lime mix. Kumar et al. [7] provides a cost-effective effects together with inadequate compaction significantly solution to problematic clayey soils by adding jute fibres. impair the durability of these roads. The ultimate effect is Erdawaty et al. [8] presented that the addition of asbuton comparatively low subgrade strength and eventually higher with waterglass could increase soil’s load capacity and pavement thickness if paved roads are to be constructed. reduce the settlement of soft soils. The design charts for flex- Based on this treatment of locally available materials has ible pavements using cement treated base are published in become necessary for satisfactory and economic construc- IRC 37-2018 [9]. Guidelines for The design of plain jointed tion of roads in these regions. Cement stabilized bases or rigid pavements for highways are published in IRC 58-2015 lime stabilized sub-bases may be provided for the construc- [10], and guidelines for design and construction of cement tion of rural roads for low volume light traffic. concrete pavements for low volume roads are published in An increasing emphasis has been placed on the use of sta- IRC SP 62-2014 [11]. Harrington et.al [12] provides a guide bilized pavement materials in recent years. Using stabilizing for evaluating existing pavements to determine if they are agents, low-quality materials can be economically upgraded good candidates for concrete overlays, selecting the appro- to the extent that these may be effectively utilized in the priate overlay system for specific pavement conditions, and pavement. Stabilized pavement materials are generally used managing concrete overlay construction work zones under in the pavement structure as base courses and sub-bases. In a traffic. Guidelines for conventional and Thin White Topping layered system of elastic materials, where the overlying lay- are published by IRC 76-2015 [13]. The design charts for ers have higher moduli of elasticity than underlying layers, 1 3 Innovative Infrastructure Solutions (2022) 7:245 Page 3 of 26 245 tensile stresses are developed at the interfaces between the Pavement design layered materials. This layered system analysis is commonly presumed to apply to a pavement where stiffer materials are The Thin White Topping (TWT) Pavements are designed as used in the upper layers. Since many stabilized materials per IRC SP 62-2014 [11]. are relatively weak in tension, any type of rational design procedure must take their tensile strength into account. (A) Name of Road: Sanaswadi Dhanore Road Tal. Shirur The key machinery required for the CIPR technique is— Dist. Pune Streau Master (Automatic Cement Spreader), recycler, pad foot roller, grader, etc. Initial design 283 Grade of concrete M30 traffic (A) CVPD Design life 20 years Design flexural 4.22 MPa Field trial stretch (n) strength = 90 days strength consid- Two roads having different types of traffic, geography and ered f = 1.1 × existing soil conditions have been selected from Pune district 0.7 × √fck in Maharashtra State under the Research and Development Traffic 5% Poisson’s ratio of 0.15 growth rate concrete Scheme of Mukhya Mantri Gram Sadak Yojana. (r) −6 Reliability 60% Coefficient of ther - 10 × 10 per (1) Sanaswadi to Dhanore Road Taluka Shirur District mal expansion (α) °C Pune % Cracking 40% Trial Concrete 200 mm (2) Pimpre to Ozare Road Taluka Indapur District Pune at the end of Thickness = with CTB design life 200 mm Preliminary data Fatigue 10% Transverse Joint 2.00 m check spacing (L) criteria for Preliminary data like subgrade soil, surface condition, car- a vehicleex- riageway width, crust thickness, rainfall and drainage con- ceeding dition have been collected. The preliminary data of the two 50 kN Wheel load road sites are as tabulated below (Table 1). Wheel load 50 kN Temperature Zone III (Maharash- Laboratory tests are conducted on subgrade soil for clas- for a single tra) sification of soil, proctor density, and CBR. Unconfined axle with Compressive Strength (UCS) is strength indicator of cement dual wheel treated base (CTB). It is conducted on existing WBM mate- Spacing of 310 mm rial with 4% cement content. According to IRC: 37-2018 [9] Wheel 7 days UCS of cement stabilized base should be minimum Tyre pres- 0.80 MPa sure (p) 4.5 to 7 MPa. The UCS test results fit in this limit, speci- fied by the Indian Road Congress (IRC). The laboratory test results are given in Table 2. Table 1 Preliminary data of Sr. No. Road name Length km Initial Traf- Carriage- Surface condition Crust two road fic CVPD way width thick- m nessmm 1 Sanaswadi To Dhanore 1.80 283 3.75 Deterioted BT 200 2 Pimpri To Ozare 0.50 102 3.00 WBM 100 Table 2 Subgrade soil properties and UCS of WBM with 4% cement Sr. no. Road name Subgrade soil classification MDD KN/m OMC % CBR % (WBM + 4% Cement) 7-day Gravel % Sand % Silt and Clay % UCS MPa 1 Sanaswadi To Dhanori 25.08 71.33 3.60 19.71 11.00 6.79 5.6 2 Pimpri To Ozare 28.03 67.70 4.27 21.67 10.81 8.00 1 3 245 Page 4 of 26 Innovative Infrastructure Solutions (2022) 7:245 Fig. 1 Typical cross section of rigid pavement A typical cross section of rigid pavement is shown in Initial traffic (A): 102 CVPD, Design thickness of M30 Fig. 1. grade TWT: 150 mm with CTB 200 mm Edge Stress using Westergaard equation Subgrade CBR: 8% σ = 2.16 MPa • Modulus of subgrade reaction for subgrade CBR 8% and Temperature stress (σ ) is calculated by equation (1) 200 mm CTB (k) = 237 MPa/m te • Edge stress σ = 3.27 MPa 0.67 × C ×  ×ΔT × E E ×  ×ΔT = − Temperature stress σ = 0.61 MPa (1) te te 2 3 × 3.91 • Combined stress (σ) = 3.88 MPa. C = correction factor based on L/l = 0.34 Since calculated combined stress (3.88 MPa) is less than l = radius of relative stiffness. design flexural strength (4.22 MPa), the design is safe. α =: coefficient of thermal expansion ΔT=: temperature differential °C E = Modulus of Elasticity of concrete in MPa Construction methodology σ = 0.16 MPa te Combined stress (σ) = wheel load stress + temperature Cement treated base stress σ = 2.16 + 0.16 = 2.32 MPa < 4.22 MPa The existing road is having a WBM/deteriorated bituminous Check for Fatigue criteria with 60% reliability as given surface. To utilize existing coarse aggregates Cold in Place by Eq. (2) Recycling (CIPR) technology has been adopted for the con- −2.222 SR struction of CTB. The machinery required for CTB work Log N = (2) 10 f 0.523 is Streau Master (Automatic Cement Spreader), Recycler, Pad foot roller, and grader. The CTB thickness requirement N = Fatigue life with combined wheel load + temperature f- is 200 mm, hence additional Wet Mix Macadam (WMM) stresses. material laid of required thickness. 4% Cement by weight SR = Sress Ratio = combined f lexural stress/f lexural basis is spread on the coarse aggregate surface with help of strength. Streau Master. The width of the spreader is 2 meters. Hence, SR = 0.56. cement is spread in half lane width in one go. Recycling of Allowable repetitions given by Eq. (2) N = 15,129,009. WBM/WMM material is done with the help of a Recycler. For rural roads fatigue criteria checked for 10% of CVPD Recycler can recycle material up to 500 mm depth. For the over design life. trial stretch, 200 mm thick CTB is required; accordingly, the Expected repetitions (N) = 10% of Total traffic over A×(1+r) −1 depth of recycling is adjusted, so that compacted 200 mm design life = 10% of . thick CTB is obtained. (Fig. 2) Water is added as per opti- N = 362,072 < N . mum moisture content (OMC) requirements at the time of As the cumulative fatigue damage factor (N/N ) is less recycling. After recycling the surface is rolled with a pad than 1; hence the design is safe. foot roller to achieve the required compaction. The surface is graded to the required profile and rolled with the help of (B) Name of Road:—Pimpre Ozare Road Tal. Indapur Dist. a smooth wheeled roller. Curing of CTB is done for 7 days Pune before laying of wearing course. 1 3 Innovative Infrastructure Solutions (2022) 7:245 Page 5 of 26 245 Fig. 4 Texturing of concrete Fig. 2 Recycling of base course with Recycler Fig. 5 Joint cutting and filling with sealant Fig. 3 Laying of PQC The curing of concrete is done for 14 days by ponding/plac- ing wet gunny (jute) bags. Light vehicles are allowed after 14 days. Heavy vehicles are allowed after 28 days. Wearing course Channels of required sizes are placed on the outer edge side Problems during construction of the carriageway. M30 grade Pavement Quality Concrete (PQC) of required thickness as per design has been provided (1) During constructing the CTB roads, it is necessary to divert traffic to alternative nearest road otherwise sur - on CTB (Fig. 3). A polythene sheet of 125-micron thickness has been laid on CTB before laying of PQC. Concrete is face profile of the freshly constructed CTB layer will get disturbed. properly compacted with the help of needle vibrators. The finished surface of the concrete is broomed with the help of (2) A set of machinery is required for construction CTB using the CIPR technique, hence it becomes uneco- a wire broomer to obtain texturing of 1.5 mm depth (Fig. 4). The transverse contraction joints at the spacing 2  meter nomical to construct smaller stretches. (3) The construction of the road should be in a continuous center to center and 3 to 5 mm width sawed to the depth 1/3 of the thickness of TWT within 24 hours after laying of stretch; otherwise indirect expenses could be increased. TWT. The joints are filled with a sealant material (Fig.  5). 1 3 245 Page 6 of 26 Innovative Infrastructure Solutions (2022) 7:245 Performance evaluation Pavement performance evaluation includes a range of quali- tative and quantitative measurements, intended to capture the structural and functional condition of pavements [14]. The information collected provides a ‘‘report card’’ of pave- ment condition at a particular point of time. Normally the collected pavement evaluation information is grouped into three broad categories, namely: (A) Serviceability (B) Structural capacity (C) Surface distress Serviceability The pavements are built for serving the traffic which repre- sents serviceability. This principle has motivated the use of a rating scale for pavement serviceability which ranges from 0 to 5. In which 0 signifies very poor and 5 signifies very good Fig. 6 FWD test rating. Serviceability of pavement is observed with rough- ness index. The roughness index test has been carried out on two constructed roads using axle mounted bump integrator. Structural capacity The capability of pavement to handle the traffic loads antici- pated over its life is known as structural capacity. There is a variety of commercially available devices for measuring in-situ pavement deflections, referred to as deflectometer. Deflectometer applies a known load to the surface and uses geophones arranged to yield a ‘‘bowl’’ of deflection meas- urements. These devices provide information not only on the structural capacity of pavement sections but also on the structural properties of their layers and the subgrade. The latter is done through back-calculation. Falling Weight Deflectometer (FWD) is used to assess the structural capac- ity of pavement [4] (Fig. 6). Response of pavement to falling Fig. 7 Rebound hammer test weight is recorded in terms of deflection and the structural capacity of pavement is worked out through back-calcula- tions. Program KUAB PVD software module is used to cal- Surface distress culate moduli and strain analysis with lifetime for required strength from respective input data. In-built calculations This component of performance evaluation involves the include calculations of modulus of elasticity for the lay- ers in a pavement, given the values for each layer thickness collection of data related to the condition of the pavement surface. Distresses are defined as the manifestations of con- and Poisson’s ratio. It uses an iterative procedure, where theoretical deflection values in a mathematical model are struction defects, as well as the damaging effects due to traf - fic, the environment, and their interactions. They encompass compared to the measured data, and the program adjusts the layer modulus until no further improvement is required. a broad variety of cracks and surface distortions. Data are typically collected manually through condition surveys. The The program then calculates the strains in the layers and works out which layer will fail first according to the strain variety of distresses encountered in concrete pavements is grouped into three main categories: cracking, surface criteria and predicts balance life. In situ strength of concrete pavement is assessed with the nondestructive testing method defects, and joint deficiencies. Joint deficiencies apply to jointed concrete pavements only. using a rebound hammer (Fig. 7). 1 3 Innovative Infrastructure Solutions (2022) 7:245 Page 7 of 26 245 (a) Cracking: Cracking appears in various forms that Wheel load allow identification of its causes. Some are fatigue-related, caused by the accumulation of fatigue damage from repeti- Heavy vehicles are not expected frequently on rural roads. tive vehicle axles, such as corner cracks. Other cracks, The maximum legal load limit on a single axle with dual either longitudinal or transverse, can be caused by traffic, wheels in India being 100 kN, the recommended design load the environment, or poor construction. The combination of on the dual wheel is 50 kN having a spacing of the wheels slab warping under thermal gradients and load may result in as 310 mm center to center. transverse cracks. Longitudinal and transverse crack severity is quantified as: Tyre pressure (i) Low: mean crack opening smaller than 3 mm. The tyre pressure is taken as 0.80 MPa for a truck carrying a (ii) Moderate: mean crack opening between 3 and 6 mm. dual wheel load of 50 kN. The effect of tyre pressure on the (iii) High: mean crack opening larger than 6 mm. wheel load stresses for the practical thickness of pavement is not significant. (b) Surface Defects Map cracking consists of intercon- nected cracks that extend only into the upper surface of the Design period and traffic growth rate slab. It may be caused by poor construction. Spalling is the result of the dislodgement of surface blocks created by map Concrete pavement for rural roads is designed for 20 years cracking. life. A traffic growth rate of 5% per year has been considered (c) Joint Deficiencies: Seals of transverse/longitudinal over the design period. joints can be damaged from a variety of causes, (e.g., split- ting or debonding due to age hardening) and result in mois- Subgrade strength ture and foreign object accumulation into the joint. Spalling is the breaking, chipping of slab edges within 0.6 m of trans- The strength of the subgrade is expressed in terms of the verse/longitudinal joints, and it is caused by either lack of modulus of subgrade reaction (k), which is determined by lateral support along a joint edge or by joints that do not carrying out a plate load test. Since subgrade strength is allow slab expansion due to the presence of foreign objects. affected by the moisture content, it is desirable to determine Performance evaluation of two constructed field stretches is it soon after the monsoon. Stresses in concrete pavement are done based on the above parameter (Table 3). not very sensitive to minor variation in k values and hence its value for a homogeneous soil subgrade may be obtained from its soaked CBR value. The minimum CBR of the sub- Design charts grade shall be 4%. The modulus of subgrade reaction for different subgrade CBR is given in Table  4. The Thin White Topping design charts are prepared for traf- fic less than 50 CVPD, 51 to 150. Cement treated base (CTB) CVPD, and less 450 CVPD with variable cement treated base thickness for different subgrade CBR values. The CTB material shall have a minimum unconfined com- The factors governing TWT pavement design are; pressive strength (UCS) of 4.5 to 7 MPa as per IRC: SP:89 Table 3 Performance evaluation of rigid pavement Sr. no. Name of road Length km Pavement composition Roughness index Structural capacity NDT Surface strength distress MPa 1 Sanaswadi To Dhanori 1.80 CTB-200 mm 2046 mm/km Good adequate 35 No TWT-200 mm Good 2 Pimpri To Ozare 0.50 CTB-200 mm 2100 mm/km Good adequate 30 No TWT-150 mm Good Table 4 Modulus of subgrade Soaked subgrade CBR 4 6 8 10 12 16 20 reaction(k) for different values of subgrade CBR k value (MPa/m) 35 42 49 54 59 65 68 1 3 245 Page 8 of 26 Innovative Infrastructure Solutions (2022) 7:245 [15] in 7/28 days curing. The strength of cementitious lay- the composite k value of pavement is improved and it is ers keeps on rising with time and an elastic modulus of considered in the design, based on subgrade CBR and CTB 5000  MPa can be considered for analysis of pavements thickness. The composite k value is given in Table 5. The with CTB layers having 7/28-day unconfined compression relation between composite k value and CTB thickness for strength values ranging between 4.5 and 7 MPa. The conven- different subgrade CBR(%) is shown in Fig.  8. tional cement treated layer should attain the above strength in 7 days, whereas lime and lime fly ash stabilized granular Concrete strength materials and soils should achieve the strength in 28 days since the strength gain rate is slow in such materials. Curing Since concrete pavements fail due to bending stresses, their of cemented bases shall be done for a minimum period of design must be based on flexural strength of concrete. The seven days before the commencement of the construction following relationship is used to determine flexural strength. of the next upper layer for achieving the required strength. √ f = 0.7 f (3) f ck Poisson’s ratio value of CTB material can be taken as 0.25. While preparing design charts for TWT the thickness of where CTB varying from 100 to 300 mm has been considered. The f = flexural strength in MPa. design of rigid pavement is based on modulus of subgrade f = characteristic compressive cube strength in MPa. ck reaction (k). Due to the provision of CTB over subgrade, Table 5 Composite modulus of CTB thickness CBR (%) subgrade reaction(k) in MPa/m in mm for different subgrade CBR and 4 6 8 10 12 16 20 CTB thickness 100 105.5 134.7 160.3 183.4 204.7 243.5 278.6 150 134.1 168.8 198.7 225.5 250.1 294.3 334 200 163.1 203.1 237.3 267.8 295.5 345.3 389.6 250 192.5 237.8 276.3 310.3 341.2 396.4 445.2 300 222.5 273 315.7 353.3 387.3 447.8 501.2 Fig. 8 Composite k value in MPa/m for different CBR(%) and CTB Thickness 1 3 Innovative Infrastructure Solutions (2022) 7:245 Page 9 of 26 245 For low volume roads, it is suggested that the 90 days strength may be used for design since concrete keeps on gaining strength with time. The 90-days flexural strength may be taken as 1.10 times the 28-day flexural strength as per IRC SP 62–2014. Minimum M30 grade concrete should be used for pavement construction of rural roads, Modulus of elasticity and Poisson’s Ratio The modulus of Elasticity E of concrete and Poisson’s ratio is taken as 30,000 MPa and 0.15, respectively. Coefficient of thermal expansion The coefficient of thermal expansion of concrete α is taken as; −6 α = 10 × 10 per °C. Fatigue behaviour of concrete pavement For most rural roads, fatigue behaviour is not so important because of a low volume of commercial vehicles. For rural road fatigue criteria with 60% reliability is used considering 40% cracking of slab at the end of design life. −2.222 SR Log N = (4) 10 f 0.523 N = Fatigue life of a pavement subjected to stresses caused by the combined effect of wheel load of 50 kN and temperature gradient. SR = Stress Ratio = Flexural stress due to wheel load and temperature Flexural strength Critical stress condition Concrete pavements are subjected to stresses due to a vari- ety of factors and the conditions which induce the highest stress in the pavement should be considered for analysis. The factors commonly considered for the design of pavement thickness are traffic loads and temperature gradients. The effects of moisture changes and shrinkage are of a smaller magnitude, and they are neglected in thickness design. The effect of the temperature gradient is very less at the corner, while it is much higher at the edge. Concrete pavements undergo daily cyclic changes of temperature differentials, the top being hotter than the bottom during the daytime and the opposite is the case during the nighttime. The conse- quent tendency of pavement slabs to curl upwards during the daytime and downwards during the nighttime and restraint offered to curling by the self-weight of pavement induces 1 3 Table 6 Thin white topping thickness for traffic less than 50 CVPD and concrete grade M30/M35/M40 CTB thick- Subgrade CBR (%) ness mm 4 6 8 10 12 16 20 Grade M30 M35 M40 M30 M35 M40 M30 M35 M40 M30 M35 M40 M30 M35 M40 M30 M35 M40 M30 M35 M40 100 140 130 125 135 130 120 130 125 120 130 120 115 125 120 115 125 115 110 120 115 110 150 135 130 120 130 125 120 125 120 115 125 120 110 125 115 110 120 110 105 115 110 105 200 130 125 120 125 120 115 125 115 110 120 115 110 120 110 105 115 110 105 115 105 100 250 130 120 115 125 115 110 120 115 110 120 110 105 115 110 105 110 105 100 110 100 95 300 125 120 110 120 115 110 120 110 105 115 110 100 115 105 100 110 100 95 105 100 95 245 Page 10 of 26 Innovative Infrastructure Solutions (2022) 7:245 Fig. 9 Thin White Topping thickness for traffic < 50 CVPD and Concrete Grade M30 Fig. 10 Thin White Topping thickness for traffic < 50 CVPD and Concrete Grade M35 1 3 Innovative Infrastructure Solutions (2022) 7:245 Page 11 of 26 245 Fig. 11 Thin White Topping thickness for traffic < 50 CVPD and Concrete Grade M40 stresses in the pavement referred to commonly curling a: radius of the equivalent circular area and it is calcu- stresses. These stresses are flexural, being tensile at the bot- lated by Eqs. (7) and (8), tom during the daytime and at the top during the nighttime. Corners have very little restraint and temperature stresses a = for single Wheel (7) in the corner region are negligible. Hence, edge stress is considered critical for the design of pavement thickness. For Thin White Topping with shorter joint spacing, top-down 0.8521P S P cracking will not take place as both wheels of the vehicle are d d d (8) a = + for dual Wheel not placed on the same panel. The maximum tensile stresses p  0.5227p in the edge region will be critical during the daytime. S : Spacing between the center of duel wheel. A. Wheel load stress at the edge is calculated using the d P : Load on one wheel. Westergaard Eq. (5). d P—Tyre pressure. 3(1 + )P Temperature stress ( σ ) te (3 + )h Bradbury’s equation is used for the computation of tem- 4 1 −  1.18(1 + 2)a perature stress. The temperature gradient across the depth Eh ln + 1.84 − + + is usually nonlinear. The compressive stress due to bi-linear 3 2 l 100ka temperature variation is subtracted. Temperature stress is (5) calculated by equation (9), σ : edge stress in MPa. h: Pavement thickness in mm. 0.67 × C ×  ×ΔT × E E ×  ×ΔT = − (9) te k: Modulus of subgrade reaction MPa/m. 2 3 × 3.91 P: Single Wheel Load, N σ : temperature stress in MPa. μ: Poisson’s ratio for concrete. te C: Correction factor. E: Modulus of elasticity of concrete in MPa. α: coefficient of thermal expansion. l: radius of relative stiffness and calculated by Eq. (6 ), 3 4 Eh (6) l = 12(1 −  )k 1 3 245 Page 12 of 26 Innovative Infrastructure Solutions (2022) 7:245 1 3 Table 7 Thin white topping thickness for traffic 51 to 150 CVPD and concrete grade M30 CTB Joint Subgrade CBR (%) thick- spac- CBR 4% CBR 6% CBR 8% CBR 10% CBR 12% CBR 16% CBR 20% ness ing m mm Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone I II, IV, III I II, IV, II I II,IV, III I II,IV, III I II,IV, III I II,IV, III I II,IV, III V, VI V, VI V,VI V,VI V,VI V,VI V,VI 100 1.5 140 140 140 135 135 135 135 135 135 130 130 135 130 130 130 130 130 130 125 130 130 2.0 145 145 145 145 145 145 140 145 145 140 140 145 140 145 145 140 140 145 135 140 145 2.5 155 155 160 150 155 155 150 155 155 145 150 155 150 155 155 145 150 155 145 150 155 150 1.5 135 135 135 135 135 135 130 130 130 130 130 130 130 130 130 125 130 130 125 130 130 2.0 145 145 145 140 145 145 140 145 145 140 140 145 140 140 145 135 140 145 135 140 140 2.5 150 155 155 150 155 155 150 155 155 145 150 155 145 150 155 145 150 155 140 150 155 200 1.5 135 135 135 130 130 130 130 130 130 130 130 130 125 130 130 125 125 130 125 125 125 2.0 140 145 145 140 145 145 140 140 145 140 140 145 135 140 140 135 140 140 135 140 140 2.5 150 155 155 150 155 155 145 150 155 145 150 155 145 150 155 140 150 150 140 145 150 250 1.5 130 130 130 130 130 130 125 130 130 125 130 130 125 125 130 125 125 125 120 125 125 2.0 140 145 145 140 140 145 135 140 145 135 140 140 135 140 140 135 140 140 130 135 140 2.5 150 155 155 145 150 155 145 150 155 145 150 155 140 150 150 140 145 150 135 145 150 300 1.5 130 130 130 125 130 130 125 125 130 125 125 130 125 125 125 120 125 125 120 125 125 2.0 140 140 145 135 140 145 135 140 140 135 140 140 135 140 140 130 135 140 130 135 140 2.5 145 150 155 145 150 155 140 150 155 140 150 150 140 145 150 135 145 150 135 140 145 Innovative Infrastructure Solutions (2022) 7:245 Page 13 of 26 245 1 3 Table 8 Thin white topping thickness for traffic 51 to 150 CVPD and concrete grade M35 CTB Joint Subgrade CBR (%) thick- spac- CBR 4% CBR 6% CBR 8% CBR 10% CBR 12% CBR 16% CBR 20% ness ing m mm Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone I II,IV, III I II,IV, III I II,IV, III I II,IV, III I II,IV, III I II,IV, III I II,IV, III V,VI V,VI V,VI V,VI V,VI V,VI V,VI 100 1.5 130 130 130 130 130 130 125 130 130 125 125 125 125 125 125 120 125 125 120 120 125 2.0 140 140 140 135 140 140 135 135 140 135 135 140 135 135 135 130 135 135 130 135 135 2.5 145 150 150 145 145 150 145 145 150 140 145 145 140 145 145 135 145 145 135 140 145 150 1.5 130 130 130 125 125 125 125 125 125 125 125 125 120 125 125 120 120 125 120 120 120 2.0 135 140 140 135 135 140 135 135 135 130 135 135 130 135 135 130 135 135 125 130 135 2.5 145 145 150 140 145 150 140 145 145 140 145 145 135 140 145 135 140 145 130 140 140 200 1.5 125 125 130 125 125 125 120 125 125 120 125 125 120 120 125 120 120 120 115 120 120 2.0 135 135 140 135 135 135 130 135 135 130 135 135 130 135 135 125 130 135 125 130 130 2.5 140 145 150 140 145 145 140 145 145 135 140 145 135 140 145 130 140 140 130 135 140 250 1.5 125 125 125 120 125 125 120 120 125 120 120 120 120 120 120 115 120 120 115 120 120 2.0 135 135 135 130 135 135 130 135 135 130 130 135 125 130 135 125 130 130 125 130 130 2.5 140 145 145 135 145 145 135 140 145 135 140 145 130 140 140 130 135 140 125 135 135 300 1.5 125 125 125 120 120 125 120 120 120 120 120 120 115 120 120 115 120 120 115 115 120 2.0 130 135 135 130 135 135 130 130 135 125 130 135 125 130 130 125 130 130 120 125 130 2.5 140 145 145 135 140 145 135 140 145 135 140 140 130 135 140 125 135 135 125 130 135 245 Page 14 of 26 Innovative Infrastructure Solutions (2022) 7:245 1 3 Table 9 Thin white topping thickness for traffic 51 to 150 CVPD and concrete grade M40 CTB Joint Subgrade CBR (%) thick- spac- CBR 4% CBR 6% CBR 8% CBR 10% CBR 12% CBR 16% CBR 20% ness ing m mm Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone I II,IV, III I II,IV, III I II,IV, III I II,IV, III I II,IV, III I II,IV, III I II,IV, III V,VI V,VI V,VI V,VI V,VI V,VI V,VI 100 1.5 125 125 125 125 125 125 120 120 120 120 120 120 120 120 120 115 120 120 115 115 120 2.0 130 135 135 130 135 135 130 130 135 130 130 130 125 130 130 125 130 130 125 125 130 2.5 140 140 145 135 140 140 135 140 140 135 140 140 130 135 140 130 135 140 130 135 135 150 1.5 125 125 125 120 120 120 120 120 120 120 120 120 115 120 120 115 115 120 115 115 115 2.0 130 135 135 130 130 130 125 130 130 125 130 130 125 130 130 120 125 130 120 125 125 2.5 135 140 140 135 140 140 135 140 140 130 135 140 130 135 135 125 135 135 125 130 135 200 1.5 120 120 120 120 120 120 115 120 120 115 120 120 115 115 115 115 115 115 110 115 115 2.0 130 130 130 125 130 130 125 130 130 125 125 130 120 125 130 120 125 125 120 125 125 2.5 135 140 140 130 136 140 130 135 135 130 135 135 125 135 135 125 130 135 120 130 130 250 1.5 120 120 120 115 120 120 115 115 120 115 115 115 115 115 115 110 115 115 110 110 115 2.0 125 130 130 125 130 130 125 125 130 120 125 125 120 125 125 120 125 125 115 120 125 2.5 135 140 140 130 135 140 130 135 135 125 130 135 125 130 135 120 125 130 120 125 130 300 1.5 120 120 120 115 120 120 115 115 115 115 115 115 110 115 115 110 110 115 110 110 110 2.0 125 130 130 125 125 130 120 125 125 120 125 125 120 125 125 115 120 125 115 120 120 2.5 130 135 140 130 135 135 125 130 135 125 130 130 120 130 130 120 125 130 115 125 125 Innovative Infrastructure Solutions (2022) 7:245 Page 15 of 26 245 Fig. 12 Thin White Topping thickness for traffic 51 to 150 CVPD, Concrete Grade M30 and Subgrade CBR 4% Fig. 13 Thin White Topping thickness for traffic 51 to 150 CVPD, Concrete Grade M30, and Subgrade CBR 6% 1 3 245 Page 16 of 26 Innovative Infrastructure Solutions (2022) 7:245 Fig. 14 Thin White Topping thickness for traffic 51 to 150 CVPD, Concrete Grade M30 and Subgrade CBR 8% Fig. 15 Thin White Topping thickness for traffic 51 to 150 CVPD, Concrete Grade M30 and Subgrade CBR 10% 1 3 Innovative Infrastructure Solutions (2022) 7:245 Page 17 of 26 245 Fig. 16 Thin White Topping thickness for traffic 51 to 150 CVPD, Concrete Grade M30 and Subgrade CBR 12% Fig. 17 Thin White Topping thickness for traffic 51 to 150 CVPD, Concrete Grade M30 and Sibgrade CBR 16% 1 3 245 Page 18 of 26 Innovative Infrastructure Solutions (2022) 7:245 Fig. 18 Thin White Topping thickness for traffic 51 to 150 CVPD, Concrete Grade M30 and Subgrade CBR 20% ΔT: temperature differential °C. thickness design chart for M30, M35, and M40 con- Temperature differentials in different zones in India are crete grades is given in Table 6. As temperature stresses taken as recommended by Central Road Research Institute are not considered in the design, spacing of joint and Table 4.1 of IRC SP 62-2014 [11]. For Thin white topping, temperature zone does not have effect on thickness the concrete thickness is less than 200 mm hence tempera- of TWT. Preferably joint spacing should be provided ture differential values in zone II, IV, V, VI are nearly the 12 to 15 times the thickness of TWT. For a particular same and hence clubbed in single group. subgrade CBR value, the TWT thickness requirement decreases with increase in CTB thickness up to certain Joint spacing extent. Also for a particular CTB thickness, the TWT thickness requirement decreases with increase in sub- The Joint spacing for concrete pavement is recommended 12 grade CBR value. Effect of CTB thickness on TWT to 15 times the thickness of concrete. From the construction thickness for concrete grade M30, M35 and M40 is point of view, joint spacing of 1.5-m, 2.0 m, and 3.00 m has shown in Figures 9, 10, 11. been considered in the design. (b) Traffic 51 to 150 CVPD: For traffic higher than 50 and less than 150 CVPD, Pavement design charts the thickness evaluation should be done based on total stresses resulting from wheel load of 50 kN and tem- Pavement design charts are prepared considering traffic, perature differential. The TWT thickness design charts Subgrade CBR, CTB thickness, grade of concrete, and trans- for M30, M35, and M40 concrete grades are given in verse joint spacing. Tables 7, 8, 9. As temperature stresses are considered in the design, joint spacing and temperature zone has (a) Traffic less than 50 CVPD: effect on thickness requirement of TWT. For a par - For traffic, less than 50 CVPD only wheel load ticular subgrade CBR value and CTB thickness, the stresses for a load of 50 kN on dual wheel need be TWT thickness requirement increases with increase in considered for thickness estimation since there is a low joint spacing. TWT thickness requirement for zone III probability of maximum wheel load and highest tem- is higher and lower for zone I. For lower joint spacing perature differential between the top and bottom of the effect of zone is insignificant. The effect of CTB thick - rigid pavement occurring at the same time. The TWT ness on TWT thickness for different temperature zones 1 3 Innovative Infrastructure Solutions (2022) 7:245 Page 19 of 26 245 1 3 Table 10 Thin white topping thickness for traffic < 450 CVPD and concrete grade M30 CTB Joint Subgrade CBR (%) thick- spac- CBR 4% CBR 6% CBR 8% CBR 10% CBR 12% CBR 16% CBR 20% ness ing m mm Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone I II,IV, III I II,IV,V,VI III I II,IV, III I II,IV,V,VI III I II,IV, III I II,IV, III I II,IV, III V,VI V,VI V,VI V,VI V,VI 100 1.5 185 185 185 185 185 185 180 180 180 180 180 180 175 175 175 175 175 175 175 175 175 2.0 195 195 195 190 190 190 190 190 190 190 190 190 190 190 190 190 190 190 190 190 195 2.5 205 205 205 205 205 210 205 205 210 205 210 210 205 210 215 205 210 215 205 215 220 150 1.5 185 185 185 180 180 180 175 175 175 175 175 175 175 175 175 175 175 175 170 170 175 2.0 190 190 190 190 190 190 190 190 190 190 190 190 190 190 190 190 190 195 190 190 195 2.5 205 205 205 205 205 210 205 210 215 205 210 215 205 210 215 205 215 220 205 215 220 200 1.5 180 180 180 175 175 175 175 175 175 175 175 175 175 175 175 170 170 170 170 170 170 2.0 190 190 190 190 190 190 190 190 190 190 190 195 190 190 195 190 190 195 190 195 195 2.5 205 205 210 205 210 210 205 210 215 205 210 215 205 215 220 205 215 220 205 215 225 250 1.5 180 180 180 175 175 175 175 175 175 170 175 175 170 170 170 170 170 170 170 170 170 2.0 190 190 190 190 190 190 190 190 195 190 190 195 190 190 195 190 195 195 190 195 200 2.5 205 210 210 205 210 210 205 215 220 205 215 220 205 215 220 205 215 225 205 215 225 300 1.5 175 175 175 175 175 175 170 175 175 170 170 170 170 170 170 170 170 170 170 170 170 2.0 190 190 190 190 190 195 190 190 195 190 190 195 190 195 195 190 195 200 190 195 200 2.5 205 210 215 205 215 215 205 215 220 205 215 220 205 215 225 205 215 225 205 220 230 245 Page 20 of 26 Innovative Infrastructure Solutions (2022) 7:245 1 3 Table 11 Thin white topping thickness for traffic < 450 CVPD and concrete grade M35 CTB Joint Subgrade CBR (%) thick- spac- CBR 4% CBR 6% CBR 8% CBR 10% CBR 12% CBR 16% CBR 20% ness ing m mm Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone I II,IV, III I II,IV, III I II,IV, III I II,IV, III I II,IV, III I II,IV, III I II,IV, III V,VI V,VI V,VI V,VI V,VI V,VI V,VI 100 1.5 180 180 180 175 175 175 170 170 170 170 170 170 170 170 170 165 165 165 165 165 165 2.0 185 185 185 185 185 185 180 185 185 180 185 185 180 185 185 180 180 185 180 185 185 2.5 195 195 200 195 200 200 195 200 200 195 200 205 195 200 205 195 200 205 195 205 210 150 1.5 175 175 175 170 170 170 170 170 170 170 170 170 165 165 165 165 165 165 165 165 165 2.0 185 185 185 180 185 185 180 185 185 180 180 185 180 180 185 180 185 185 180 185 185 2.5 195 200 200 195 200 200 195 200 205 195 200 205 195 200 205 195 205 210 195 205 210 200 1.5 170 170 170 170 170 170 165 165 165 165 165 165 165 165 165 165 165 165 160 165 165 2.0 180 185 185 180 185 185 180 180 185 180 185 185 180 185 185 180 185 185 180 185 190 2.5 195 200 200 195 200 205 195 200 205 195 205 210 195 205 210 195 205 210 195 205 210 250 1.5 170 170 170 165 165 165 165 165 165 165 165 165 165 165 165 160 165 165 160 165 165 2.0 180 185 185 180 180 185 180 185 185 180 185 185 180 185 185 180 185 190 180 185 190 2.5 195 200 205 195 200 205 195 205 210 195 205 210 195 205 210 195 205 210 195 205 215 300 1.5 170 170 170 165 165 165 165 165 165 165 165 165 160 165 165 160 165 165 160 160 165 2.0 180 180 185 180 185 185 180 185 185 180 185 185 180 185 190 180 185 190 180 185 190 2.5 195 200 205 195 205 210 195 205 210 195 205 210 195 205 210 195 205 215 195 205 215 Innovative Infrastructure Solutions (2022) 7:245 Page 21 of 26 245 1 3 Table 12 Thin white topping thickness for traffic < 450 CVPD and concrete grade M40 CTB Joint Subgrade CBR (%) thick- spac- CBR 4% CBR 6% CBR 8% CBR 10% CBR 12% CBR 16% CBR 20% ness ing m mm Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone Zone I II,IV, III I II,IV, III I II,IV, III I II,IV, III I II,IV, III I II,IV, III I II,IV, III V,VI V,VI V,VI V,VI V,VI V,VI V,VI 100 1.5 170 170 170 170 170 170 165 165 165 165 165 165 165 165 165 160 160 160 160 160 160 2.0 180 180 180 175 175 180 175 175 175 175 175 175 175 175 175 175 175 180 175 175 180 2.5 190 190 190 190 190 195 190 190 195 190 195 195 190 195 195 190 195 200 185 195 200 150 1.5 170 170 170 165 165 165 165 165 165 160 160 160 160 160 160 160 160 160 155 160 160 2.0 175 175 180 175 175 175 175 175 175 175 175 175 175 175 180 175 175 180 175 175 180 2.5 190 190 195 190 195 195 190 195 195 190 195 200 190 195 200 185 195 200 185 195 200 200 1.5 165 165 165 165 165 165 160 160 160 160 160 160 160 160 160 155 160 160 155 155 160 2.0 175 175 175 175 175 175 175 175 175 175 175 180 175 175 180 175 175 180 170 175 180 2.5 190 195 195 190 195 195 190 195 200 185 195 200 185 195 200 185 195 200 185 195 205 250 1.5 165 165 165 160 160 160 160 160 160 160 160 160 155 160 160 155 155 160 155 155 155 2.0 175 175 175 175 175 175 175 175 180 175 175 180 175 175 180 170 175 180 170 175 180 2.5 190 195 195 190 195 200 185 195 200 185 195 200 185 195 200 185 195 205 185 195 205 300 1.5 160 160 160 160 160 160 160 160 160 155 160 160 155 155 160 155 155 155 155 155 155 2.0 175 175 175 175 175 180 175 175 180 170 175 180 170 175 180 170 175 180 170 175 180 2.5 190 195 200 185 195 200 185 195 200 185 195 200 185 195 205 185 195 205 185 195 205 245 Page 22 of 26 Innovative Infrastructure Solutions (2022) 7:245 Fig. 19 Thin White Topping thickness for traffic < 450 CVPD, Concrete Grade M30 and Subgrade CBR 4% Fig. 20 Thin White Topping thickness for traffic < 450 CVPD, Concrete Grade M30 and Subgrade CBR 6% and joint spacing for M30 grade concrete and different (c) Traffic less than 450 CVPD: subgrade CBR is shown in Figures 12, 13, 14, 15, 16, 17, 18. 1 3 Innovative Infrastructure Solutions (2022) 7:245 Page 23 of 26 245 Fig. 21 Thin White Topping thickness for traffic < 450 CVPD, Concrete Grade M30 and Subgrade CBR 8% Fig. 22 Thin White Topping thickness for traffic < 450 CVPD, Concrete Grade M30 and Subgrade CBR 10% For traffic exceeding 150 CVPD, fatigue can be a real thickness is designed considering combined stresses due problem, and thickness evaluation based on fatigue frac- to wheel load edge stress for the dual wheel of 50 kN and ture with 60% reliability should be considered. Pavement temperature gradient. Also, concrete pavement is checked 1 3 245 Page 24 of 26 Innovative Infrastructure Solutions (2022) 7:245 Fig. 23 Thin White Topping thickness for traffic < 450 CVPD, Concrete Grade M30 and Subgrade CBR 12% Fig. 24 Thin White Topping thickness for traffic < 450 CVPD, Concrete Grade M30 and Subgrade CBR 16% for fatigue criteria. Assuming 10% of total traffic is having number of repetitions is computed considering 60% reliabil- an axle load of more than 100 kN, the expected number of ity from the fatigue equation. Cumulative fatigue damage is vehicles is computed over the design period. The allowable computed and it should be less than 1. The TWT thickness 1 3 Innovative Infrastructure Solutions (2022) 7:245 Page 25 of 26 245 Fig. 25 Thin White Topping thickness for traffic < 450 CVPD, Concrete Grade M30 and Subgrade CBR 20% charts for concrete grades M30, M35, and M40 are given in subgrade CBR for rural roads. From the development of Tables 10,11,12. The TWT thickness requirement increases design charts following are the significant observations, with increase in joint spacing. The effect of zone is insig- nificant keeping all other parameters constant. TWT thick - Composite modulus of subgrade reaction (k) value ness requirement decreases with increase in CTB thickness increases with an increase in thickness of CTB. for 1.5 meter joint spacing The TWT thickness requirement The optimum thickness of TWT can be obtained from decreses with increase in subgrade CBR value upto certain Design Chart and the economy in the Pavement design extent for same CTB thickness and joint spacing. The effect can be achieved. of CTB thickness on TWT thickness for different tempera- • For low CBR Subgrade value, increase in CTB thickness ture zones and joint spacing for M30 grade concrete and can reduce TWT Thickness only up to the certain extent different subgrade CBR is shown in Figures 19, 20, 21, 22, • For an increase in Joint spacing the required TWT thick- 23, 24, 25. ness increases. • For Joint spacing of 1.5 m, TWT thickness is the same for all zones. Conclusions • For Joint spacing 2.0  m and 2.5-m, TWT thickness requirement is higher for Zone III and lower for Zone I. The design charts for Thin White Topping with variable thickness of cement treated base and different subgrade CBR The Thin White Topping pavement structures over ade- are prepared for rural roads. With Cold In Place Recycling quate base support would have superior load carrying capa- technique, existing local material can be utilized and the bility hence Thin White Topping pavement structure rec- strength of subgrade and subbase shall be improved with ommended as a pavement design alternative in low-volume cement stabilization. From field experiments the perfor - rural roads. The construction of rural roads with CTB using mance evaluation rating after two years of construction is the CIPR technique is an effective and environmentally good for pavement constructed with CTB using CIPR tech- friendly solution. nique and Thin White Topping. Surface cracking, potholes, Acknowledgements I am thankful to Rural Development Department, rutting, or any defects are not observed. Thin White Topping Government of Maharashtra for sanctioning the road works in Mukhya thickness design charts of M30, M35 and M40 are developed Mantri Gram Sadak Yojana under research and development scheme. for varying thickness of cement treated base and different 1 3 245 Page 26 of 26 Innovative Infrastructure Solutions (2022) 7:245 Authors' contribution Designed and developed the methodology 2. Ramachandra V (2011) White topping: an excellent solution for for the construction of rural roads with Cement Treated Base. Trial pavement rehabilitation NBM & CW stretches are constructed using cement treated base with Cold In Place 3. Kadiyali LR and Associates (2010) Handbook on Cement Con- Recycling technology. Performance evaluation of these roads has been crete Roads Cement Manufacturer’s Association, New Delhi carried out after two years of construction. Thin White Topping thick- 4. Skanda Kumar BN, Suhas R, Bhavan V (2014) Performance ness design charts with variable cement treated base thickness for dif- evaluation of thin white topping. Int J Res Eng Technol. https:// ferent subgrade CBR values and Traffic are prepared for rural roads. doi. org/ 10. 15623/ ijret. 2014. 03070 68 These charts are useful for construction of rural roads to the Field 5. Li Z, Vandenbossch JM (2013) Redefining the failure mode for Engineers. thin and ultra-thin white topping with a 1.8 x 1.8 m (6 x 6-ft) joint spacing. Transp Res Board Pittsburgh. https:// doi. org/ 10. 3141/ 2368- 13 Funding The construction of trial roads is sanctioned in Mukhya Man- 6. Bagui SK (2012) Pavement design for rural low volume roads tri Gram Sadak Yojana Research and Development Scheme by the using cement and lime treatment base. Jorden J Civil Eng Government of Maharashtra. The construction cost of two roads is as 6:293–303 below, Construction of Sanaswadi to Dhanore Road Taluka: Shirur 7. Kumar S, Sahu A, Naval S (2020) Influence of jute fibre on CBR Dist: Pune Cost: Rs. 472.73 lakhs. Construction of Pimpre to Ozare value of expansive soil. Civil Eng J. https://doi. or g/10. 28991/ cej- Road Taluka: Indapur Dist: Pune Cost: Rs. 270.83 lakhs. 2020- 03091 539 8. Erdawaty, Harianto T, Muhiddin AB, Arsyad A (2020) Experi- Declarations mental study on bearing capacity of alkaline activated granular asphalt concrete columns on soft soils. Civil Eng J. https://doi. or g/ Conflict of interest On behalf of all authors, the corresponding author 10. 28991/ cej- 2020- 03091 623 states that there is no conflict of interest. 9. IRC: 37-2018, “Guidelines For Design of Flexible Pavements” (Fourth Revision), Indian Road Congress Data availability Some or all data, models, or code that support the 10. IRC: 58-2015, “Guidelines for The Design Of Plain Jointed findings of this study are available from the corresponding author upon Rigid Pavements For Highways”, (Fourth Revision) Indian Road reasonable request. Congress 11. IRC SP 62-2014: “Guidelines for Design and Construction of Cement Concrete Pavements for Low Volume Roads”, Indian Open Access This article is licensed under a Creative Commons Attri- Road Congress bution 4.0 International License, which permits use, sharing, adapta- 12. Harrington D, Snyder & Associates, Inc.Gary Fick, Trinity Con- tion, distribution and reproduction in any medium or format, as long struction Management Services, Inc., (2014) Guide to Concrete as you give appropriate credit to the original author(s) and the source, Overlays Sustainable Solutions for Resurfacing and Rehabilitating provide a link to the Creative Commons licence, and indicate if changes Existing Pavements” American Concrete Pavement Association. were made. The images or other third party material in this article are https:// doi. org/ 10. 13140/ RG.2. 1. 3106. 4724 included in the article's Creative Commons licence, unless indicated 13. IRC: SP: 76-2015, “Guidelines For Conventional and Thin White otherwise in a credit line to the material. If material is not included in Topping” ( First Revision), Indian Road Congress the article's Creative Commons licence and your intended use is not 14. Delatte N (2008) Concrete pavement design construction and per- permitted by statutory regulation or exceeds the permitted use, you will formance. Taylor & Francis, London, New York need to obtain permission directly from the copyright holder. To view a 15. IRC:SP:89-2018 (Part II), "Guidelines for the Design of Stabilised copy of this licence, visit http://cr eativ ecommons. or g/licen ses/ b y/4.0/ . Pavements (Part II)," Indian Roads Congress References 1. Wu Z, Rupnow T, Mahdi MI (2017) Roller compacted concrete over soil cement under accelerated loading, Louisiana Transp Res Center LA. https:// doi. org/ 10. 1061/ 97807 84479 216. 038 1 3

Journal

Innovative Infrastructure SolutionsSpringer Journals

Published: Aug 1, 2022

Keywords: Cement treated base (CTB); Thin white topping (TWT); Cold in place recycling (CIPR); Rural roads; Stabilization; California bearing ratio (CBR)

References