Rigid Pavements

In this study, the shape of coarse aggregate particles has been related to the workability and compressive strength of cement concrete for rigid pavements. The shape characteristics such as elongation, flatness, shape factor, and sphericity were determined. Also,the slump and compressive strength of cement concrete were determined for various shapes of coarse aggregate. The test results indicated that there is a good correlation between some shape properties of aggregate, workability, and compressive strength.The highest compressive strength at different ages noted with concrete made from different shapes of coarse aggregates. Results indicate that the strength of concrete varies as a function of the shape of the coarse aggregate, which leads to the conclusion that the shape of aggregate shall be considered as an important parameter in deciding the suitability of coarse aggregate to prepare cement concrete for rigid pavements. I. INTRODUCTION To provide a stable and even surface for the traffic, the roadway is always provided with a suitably designed and constructed pavement structure. Thus, a pavement consisting of a few layers of pavement materials is constructed over a prepared layer of sub-grade to serve as a carriageway. Based on design consideration pavements can be classified as-Rigid pavements and Flexible pavement. Flexible pavements can be defined as the one consisting of a mixture of asphaltic or bituminous material and aggregates placed on a bed of compacted granular material of appropriate quality in layers over the subgrade. Rigid pavements are those, which possess noteworthy flexural strength or flexural rigid. The rigid pavement has the slab action and is capable of transmitting the wheel load stresses through a wider area below. Cement concrete is a composite material produced by the homogenous mixing of selected proportions of water, cement, and aggregates (fine and coarse). Strength is the most desired quality of a good concrete. It should be strong enough, at hardened state, to resist the various stresses to which it would be subjected. Aggregates are the most important constituents in cement concrete. For a long time aggregates were considered as inert materials, but after 1940 it was brought out that aggregates do show some reactivity. The mere fact that aggregates constitute 70-80% of the volume of concrete, their impact on various characteristics is undoubtedly considerable. Aggregates give the body to the concrete, reduce shrinkage, and affect the economy. Among all the characteristics of aggregates, the shape is most important because it affects the workability and compressive strength of cement concrete. Aggregates form the major portions of pavement structure and aggregates have to bear stresses occurring due to wheel loads on the pavement and on the surface-course they have to resist wear due to the abrasive action of traffic. Therefore, the properties of aggregates are of considerable significance to the highway engineers. Significant findings indicate that aggregate plays a more "active" role than was previously believed, and a better understanding will result from further research. Several authors have indicated the need for more research to determine the effect of aggregate particle shape on the properties of concrete at present there is only alimited amount of information concerning the effect of aggregate particle shape on concrete proportioning, workability, and strength. This lack of information is reflected in specifications that place conservative limits on allowable amounts of particles of certain shapes. The present study was undertaken to investigate the effect of different types of coarse aggregate effect on the fresh and hardened Portland cement concrete behavior by a means of aggregate shape indexes such as elongation, flatness, roundness, shape factor, and sphericity.

2,3 B.tech final year student jbit, Dehradun (u.k) Abstract— The development of design have been discussed adopted various types methods use. The Hadi and Arfiadi Method presents a formulation for the optimum rigid road pavement design by genetic algorithm, a new method. The Westergaard's Method determines the stresses in the rigid concrete slab and also the pressure-deformation curve which depend upon the relative stiffness of the slab and the subgrade. Razouki and Al-Muhana also developed stress charts similar to Westergaard's method. The paper reveals that the effects on the maximum bending tensile stress are quite significant due to the modulus of subgrade reaction, modulus of elasticity of concrete and slab The Maharaj and Gill method have performed axisymmetric finite element analysis by varying parameters, the thickness of pavement, pressure and elastic modulus of subgrade. The advantage of this method is that four types of design charts have been presented which other methods have note done. First type of design chart has been plotted between thickness of pavement and nodal deflections for various pressures for a particular elastic modulus of soil. Second type of design chart has been plotted between thickness of pavement and element stress for various pressures for a particular elastic modulus of soil. The third type of design chart has been plotted between thickness of pavement and nodal deflections for various elastic moduli of subgrade for a particular pressure. Each of the design charts has three parameters. For two known parameters, the third parameter can be obtained.

In many countries around the world, the adversative environmental impacts of amassing waste tyres have led to investigate different options for disposal of waste tyres. Waste rubber is a foremost concern worldwide.In 2005, more than 10 billion tires were disposed of worldwide and around one billion tires are pulled back from utilize every year. By 2030, this amount could reach up to 1200 million tires being disposed of. In 2011, it was evaluated that, around the world, roughly four billion waste tires were in landfills and reserves. One opportunity to reduce this environmental concern is for the construction industry to consume a high number of recycled tyres accumulated in stashes. There are different concerns regarding the introduction of rubber into concrete. Making a homogenous mix containing even distribution of rubber is a complicated task and also severe decrease of concrete strength limits the rubber content. Moreover, replacing a portion of fine aggregates with low-stiffness rubber particles raises concerns regarding the generated shrinkage and cracking of crumb rubber concrete. This review investigates these concerns thoroughly and provides a comprehensive know-how of crumb rubber concrete characteristics, using crumb rubber in terms of coarse aggregate as well as fine aggregate.

Pekerjaan beton seperti ini umumnya terdapat pada pekerjaan pengecoran (rigid pavement). Biasanya pemerintah yang mengadakan lelang sebuah paket proyek rigid menggunakan akan memasukkan beton mutu sedang dan rendah dalam analisa, itu artinya mengharuskan kita membuat metode pelaksanaan untuk pekerjaan beton ini.

This paper presents the mechanical, durability and microstructure characteristics of cement treated recycled asphalt (CTRA) bases and sub-bases material produced by varying the percentage of virgin aggregate (VA), recycled asphalt aggregate (RA), and cement content. Modified proctor method of compaction was used to prepare cylindrical specimens at 2.5, 5.0, 7.5, and 10.0% cement contents (% by wt. of aggregate) with different blends of VA and RA. Durability tests were carried out to evaluate the performance of mixtures under repeated wetting and drying in the tropical climate. Experimental results revealed that the addition of cement in CTRA had more effect on mechanical and durability properties compared to RA content. The CTRA mixtures were found to be more ductile albeit lower values of elastic modulus. Scanning Electronic Microscope (SEM) and Energy Dispersive X-ray Spectroscopy (EDS) analysis manifest that large amount of Ettringite and higher the Si/Ca ratio in CTRA compared to cement treated mixtures without RA. The higher proportion of these products signify the detrimental effect in mechanical properties. Cost analysis for a typical pavement section demonstrate that the cost-saving of the pavement section with CTRA mixtures observed to be in the range of 26–32% under varying cement and RA contents compared to the pavement section without CTRA. It was found that these mixtures can be used as a replacement for granular bases and sub-bases in flexible pavements and/or bases for concrete pavements instead of roller-compacted concrete.

Link: https://www.amazon.com/dp/8797231703

This book introduces purely mechanistic models that are of particular relevance to the pavement engineering profession. It commences with a short recap of basic mechanics concepts, and then delves into topics such as viscoelasticity, elastic half-space solutions, and mechanics of supported plates. Given that all pavement design and analysis approaches are founded on some mechanistic logic, the text essentially offers a universal and long-lasting reference to practitioners and engineering students.

In India, road network is the world's second largest. It is 3.5 million km including both paved and unpaved surfaces. The major types of materials are used to construct the roads in the country are, bitumen and concrete. Concrete is a superior material in many counts, a very small share is used for road construction. Due to increase of utility of cement, many environmental problems are faced at the National level. It is necessary to think about the materials which can be used as alternative in the concrete. The use of specific amount of Alccofine in replacement of cement provides better strength. It is very much essential to develop profitable building materials from Alccofine. The innovative use of Alccofine in concrete making formula as a cement replacement material was tested as an alternative to traditional concrete in the present study. To find optimum dosage of Alccofine, Cement is replaced by Alccofine in the range of 0%, 5%, 10%, 15%, 20%, 25% & 30% by weight for M-40 grade concrete. Concrete mixtures were produced, tested and compared in terms of compressive and flexural strength with the conventional concrete. These tests were carried out to evaluate the mechanical properties for 7, 14 and 28 days. The present study is focused on investigating the behaviour of concrete while replacing Alccofine in different proportion in concrete.

In recent years, the use of rigid concrete overlay has become increasingly popular in bridge deck, highway and airport pavements and industrial floor rehabilitation. The main purpose of an overlay is to extend the service life of the structure by providing protection from the penetration of aggressive agents and water and a durable wearing surface. Moreover the overlay provides adequate load bearing capacity, which is compatible with the loading of the pavement and bridge deck. The superior ductility and improved durability characteristics of Engineered Cementitious Composites (ECC) suggest that they could be used as an attractive alternative to conventional overlay materials. In this study, the performance of ECC as pavement overlay material with different thicknesses is investigated. Two different ECC-overlay mixture designs are investigated: one with high strength and moderate ductility, and the other with moderate strength and high ductility. Micro-silica concrete (MSC), generally used as overlay material, is also prepared as a control mixture. Monolithic specimens’ compressive strength, flexural strength, drying shrinkage and restrained shrinkage, and layered composite beam flexural strength and reflective cracking characteristics are investigated as performance criteria. The test results show that, for the same geometry and loading conditions, layered ECC beams have a significantly increase of both load carrying capacity and deformability by deflection at ultimate load, and shows better crack width control in comparison with MSC composite beam.

h i g h l i g h t s Mechanical properties of RCCP slightly decreased as a result of adding waste sand. Adding nano SiO 2 improved the mechanical properties of RCCP. The optimum content of Nano SiO 2 for RCCP was determined. Increasing the waste materials' content led to an increase in skid resistance. The mixes containing glass waste showed the highest abrasion resistance. a b s t r a c t This study deals with the use of waste materials as replacement of fine aggregate in roller-compacted concrete pavement (RCCP). To achieve this, waste ceramic, waste concrete, and waste glass were initially crushed and mixed and then replaced natural fine aggregate at varying amounts in RCCP. Furthermore, to mitigate the probable negative effects of waste aggregates and also to improve the mechanical properties of cement paste, nano SiO 2 was employed in the mixes design. After preparing the mixes, Vebe time, com-pressive strength, splitting tensile strength, water absorption, abrasion resistance, and skid resistance were measured. The results show that more than 40% of sand replacement with waste materials could have a negative effect on the properties of RCCPs. However, this impact is negligible up to 10% of waste material proportions. The compressive strength of the mixes containing waste materials was lower than that of the control mix, except for the sample containing 10% ceramic waste. In terms of water absorption, mixes with waste materials had higher water absorption than the control mix. Besides, abrasion somewhat increased as a result of adding waste materials, except for the samples containing 10% glass and 10% ceramic wastes that showed a slight decrease. Moreover, mixes with waste materials had higher skid resistance than the control mix. Overall, waste ceramic mixes showed better mechanical properties and waste glass mixes had better performance in terms of water absorption. In addition, using nano SiO 2 leads to improve the mechanical properties of the RCCP; the optimum content of nano SiO 2 has determined to be 0.7% of cement weight.

Roads are of vital importance to make a nation rich and develop. A well-connected road network is required for industrial as well as civilization growth. This paper consists of a review on the methodologies followed in rigid pavement design. There are various methods of rigid pavement design. Rigid pavement design procedure explained in this paper. I.

Rehabilitation of existing jointed plain concrete pavements (JPCP) by using unbonded jointed plain concrete overlay is increasingly being used all over United States. The design and performance of un-bonded overlays is affected by various factors including climate, traffic volume, concrete material properties, existing pavement condition and future design life. Modulus of elasticity/stiffness of concrete is an important material property that has significant effects on the performance of concrete pavements and many researchers have acknowledged it. But there has not been much research on effects of elastic modulus on performance of unbonded overlays. This study focuses on the impact of variability of elastic modulus of concrete on the mechanistic-empirical performance predictions of un-bonded JPCP overlays. Simulations were conducted using pavement ME design software with varying elastic modulus values and keeping all other design factors as constant. The results indicated that with decrease in elastic modulus values, the performance of un-bonded JPCP overlay is adversely affected with increased transverse cracking. The adverse effects of lower elastic modulus can be compensated by increasing the thickness of overlay concrete slab or by decreasing the transverse joint spacing and obtaining improved overlay performance. INTRODUCTION Unbonded concrete overlay is a layer of concrete placed over an existing pavement (flexible, rigid or composite), with a separation layer which is usually hot mix asphalt (HMA) layer, to improve the performance of the existing pavement. The main purpose is to preserve and extend pavement service for years beyond the original design life. Concrete overlays can accommodate all combinations of design life and traffic loading. Their thickness can vary from 2 to 10 inches or even greater, depending on the existing pavement condition, anticipated traffic volume and desired design life. There are various design factors, which need to be considered for effective designing of concrete overlays. These include future design life, traffic volume, climate, existing pavement condition, joint details and properties of the

Sand is an accumulation of grains of mineral matter derived from the disintegration of rocks. It is distinguished from gravel only by the size of the grains or particles. Sand deposits of varying gradation are available in different regions of the world. The prime use of sand, as fine aggregate is in the manufacture of concrete. As fine aggregate comprises up to 30% of the total volume of concrete, consequently gradation and fineness modulus of sand are among principal factors affecting the performance of fresh and hardened concrete. For the purpose of this study, eight sand deposits were selected from various regions of Pakistan. The grain size distribution was compared with the ASTM gradation limits recommended for concrete. It was revealed that only two sands satisfy the ASTM gradation limits while all the others do not comply being on the finer side. For betterment of the construction industry, a sand optimization technique was developed. The optimization phase consisted of sieving the crusher fines and mixing different fractions of crusher fines with the natural sand in different combinations to get desired sand gradation. The optimized gradation curves matched with the ASTM limits and the optimized fineness modulus reached within the ASTM limits. The concrete made with optimized sands showed up to 39% increase in compressive strength. The composition of mineral constituents was also evaluated through x-ray diffraction and x-ray fluorescence, which indicated that the fine aggregate having higher silica content resulted in concrete with higher strength as compared to the one with higher calcium content. It was concluded that fine graded sands could be used in concreting after optimization that will reduce the huge transportation costs of using coarse sand from far-flung areas.

To determine performance of rigid pavement, pavement engineers should not only conduct stress, curling , and deflection analysis, but also understand weather conditions and subgrade quality effects on rigid pavement performance well. This study aims to analyze and visualize the mechanical behaviors of rigid pavement in terms of stress, curling, and deflection using the KENPAVE Program under different curling temperature and subgrade quality. Besides, this study also evaluated temperature differential and k-value effects on the stress, curling, and deflection behavior of concrete pavement. The findings revealed that there is a linear correlation between stress and both k-value and curling temperature, with the latter having more significant impact in controlling stress than the former. However, even though curling is not affected by subgrade quality, it significantly depends on the temperature differential since a higher curling temperature produces higher curling behavior. Lastly, a higher temperature differential produces greater deflection, but a higher k-value produces smaller deflection. Nevertheless, deflection behavior has a more significant curve and the position of the highest deflection shifted towards the center of the slab as the curling temperature and subgrade quality increase.

The work reported in this paper is based on a laboratory study carried out to investigate the feasibility of using copper slag, a by-product of copper refineries, as a partial replacement of sand in the preparation of pavement quality concrete (PQC) and dry lean concrete (DLC) mixes. A control mix for PQC was prepared with 400 kg/m 3 of ordinary Portland cement (OPC) and water – cement (w– c) ratio of 0.40. Other concrete mixtures were then prepared by substituting 20%, 40%, 60%, 80% and 100% copper slag in control mix. Workability and bleeding of green concrete, compressive strength, flexural strength at 7 and 28 days, drying shrinkage and abrasion resistance were measured for all the concrete mixtures. DLC mixtures were designed with 150 kg/m 3 of OPC and different blends of stone dust with 20%, 40%, 60% and 80% copper slag as fine aggregate. DLC mixes were then prepared with different water contents with a view to find out the optimum water content for achieving maximum density, and corresponding compressive strength at 7 and 28 days for each blend of stone dust and copper slag. The laboratory test results showed that the compressive strength of PQC 7 and 28 days was not affected by inclusion of any content of copper slag as fine aggregate in the concrete mixture. Small gradual increase in flexural strength at 28 days was observed with an increase in copper slag content. Drying shrinkage of PQC decreased with the increase in slag and the decrease in stone dust content. Abrasion resistance of concrete mixes containing slag was observed to be less as compared with that of non-slag concrete. Compressive strength of DLC decreased with the increase in copper slag content beyond 40%. Keeping in view the strength and other important requirement of PQC such as cohesiveness, segregation, finishing, texturing, shrinkage and abrasion resistance, it was concluded that a blend of stone dust with copper slag content up to 40% could be used as fine aggregate for PQC as well as DLC.

This paper presents a technical proposal for the application of experimental designs in the construction processes of civil works, specifically in the manufacture of concrete for rigid pavements. Currently is still does not apply these technological advances, or any application of research methods that allows optimizing processes to more satisfactory levels, despite the advantages and benefits they provide in terms of achieving unexpected performance and significant savings of component materials. The experimental design model is a classic statistical model whose objective is to determine if the independent factors influence in a variable of interest in this case the modulus of breakage of the concrete or in another important factor, during the bending test. The answer surface methodology is based on the experimentation in three stages, the results achieved allow locating an optimal area where the adjusted values lead to reduced consumption of them and expanding the strength of the ...

The performance of jointed plain concrete pavement is affected by various design parameters including mechanical and thermal properties of concrete. Out of these, coefficient of thermal expansion, elastic modulus and modulus of rupture are a few important ones and to evaluate the effects of these material properties on pavement performance, simulations were carried out in MEPDG. All other design parameters such as traffic, design life, climate and road bed soil conditions were considered as constant and pavement performance was evaluated. The simulation results appreciated that with an increase in coefficient of thermal expansion of concrete, the pavement performance was adversely affected. In addition, with an increase in elastic modulus and modulus of rupture values of concrete, the strength of concrete increases and resultantly an improved pavement performance was obtained. It became evident that these material parameters should be carefully considered while designing a rigid pavement.

From the past few years, the building and maintenance of high-quality roadways is vital. And nowadays, ministry of road transport and highways is shifting more on rigid pavements because of its good characteristics. The cost factor is the primary concern in every project. With the right design, even a slight reduction in the thickness of the concrete slab can save the project cost. As a result, an attempt was undertaken to build a two-lane, two-way National highway with variable concrete grades. The analysis has been carried out with variable slab thickness, different shoulder types and variable panel size of slab in which the cost has been optimized.

During the last three decades, concrete pavement or rigid pavement became a widely used alternative of flexible pavement (asphalt pavement) at freeways and highways with high traffic of heavy vehicles, due to its durability, long life, and less need of maintenance; however, the cost of construction for rigid pavement is very high compared to asphalt pavement. Developing a new concrete mixture to increase the performance and reducing the required thickness of concrete pavement became an important issue in rigid pavement design in order to reduce the high construction cost. In this study, a new concrete mixture was developed using specific amounts of steel fibers and steel slag (as a supplementary cementing material to replace a part of the cement). Several mixtures with different concentrations of fibers were prepared, and samples were tested for workability, early flexural strength, and ultimate flexural strength. The results showed that the new concrete mixture could achieve an inc...

This paper presents a technical proposal for the application of experimental designs in the construction processes of civil works, specifically in the manufacture of concrete for rigid pavements. Currently is still does not apply these technological advances, or any application of research methods that allows optimizing processes to more satisfactory levels, despite the advantages and benefits they provide in terms of achieving unexpected performance and significant savings of component materials. The experimental design model is a classic statistical model whose objective is to determine if the independent factors influence in a variable of interest in this case the modulus of breakage of the concrete or in another important factor, during the bending test. The answer surface methodology is based on the experimentation in three stages, the results achieved allow locating an optimal area where the adjusted values lead to reduced consumption of them and expanding the strength of the concrete.

High strength concrete (HSC) is the most widely used material and is presented in many different constructions such as rigid pavement. Concrete has a low tensile strength, limited fatigue life, and is characterized by brittle failure resulting in almost complete loss of loading capacity. HSC reinforced with fibers has displayed great performance in both fresh and hardened states. Recently, the use of single fiber has increased in the rigid pavement and the study of its effect on the properties of concrete. It was found that there is a need to study and compare the effect of adding hybrid fiber to concrete mixture to improve the behavior and properties of concrete. This study investigates the optimization of HSC reinforced with steel fiber by different percentages (0% to 1%), polypropylene fiber (0.0% to 0.26%) and the hybridization of steel fiber and polypropylene fiber as 1% volumetric fractions (0.8% + 0.2%), (0.7% + 0.3%) and (0.6% + 0.4%), respectively. The slump value, compressive strength, tensile strength, and flexural strength are determined. Abrasion resistance and water absorption are also measured. The fiber percentage is adjusted to alter the brittle failure. The results showed that adding fibers to the concrete mixture decrease both slump and abrasion, while increasing permeability, tensile and compressive strength.

The format of the design and performance prediction of rigid pavements was reformed with the advent of Pavement mechanistic-empirical (ME) design procedure, which now serves as the state-of-the-art tool in pavement design. Various state agencies have either completed or in the process of calibration of distress prediction models and characterization of concrete materials to provide accurate inputs required by Pavement ME design software. There are numerous concrete properties for which input data is required in ME design software, but with previous research, it was found that the concrete strength and thermal properties including elastic modulus, modulus of rupture and coefficient of thermal expansion (CTE) are the most important ones that affect the design and performance of rigid pavements. Accurate rigid pavement design is heavily dependent on accuracy of these material inputs. This study is part of a New Mexico Department of Transportation (NMDOT) research project that focuses on the development of guidelines for characterizing Portland cement concrete (PCC) materials for paving mixes being used in New Mexico. Concrete mixes with 5 different coarse aggregates were tested for these pivotal concrete properties at the curing age of 7, 14, 28 and 90 days, and for CTE at 28 days. The laboratory test results represent level 1 PCC material inputs. The data collected offered an excellent opportunity to validate and refine the ME default level 2 models for estimating flexural strength and elastic modulus based on compressive strength data. The data demonstrated a slight deviation from the nationally calibrated models. CTE values of concrete based on aggregate type were established for these paving mixes. Further analysis verified the benefit of using the level 1 inputs over the default level 3 inputs for accurate pavement design and performance prediction. It was also highlighted that transverse cracking is the most significantly affected performance parameter between the pavement designed with level 1 and level 3 material inputs.

h i g h l i g h t s Mechanical properties of RCCP slightly decreased as a result of adding waste sand. Adding nano SiO 2 improved the mechanical properties of RCCP. The optimum content of Nano SiO 2 for RCCP was determined. Increasing the waste materials' content led to an increase in skid resistance. The mixes containing glass waste showed the highest abrasion resistance. a b s t r a c t This study deals with the use of waste materials as replacement of fine aggregate in roller-compacted concrete pavement (RCCP). To achieve this, waste ceramic, waste concrete, and waste glass were initially crushed and mixed and then replaced natural fine aggregate at varying amounts in RCCP. Furthermore, to mitigate the probable negative effects of waste aggregates and also to improve the mechanical properties of cement paste, nano SiO 2 was employed in the mixes design. After preparing the mixes, Vebe time, com-pressive strength, splitting tensile strength, water absorption, abrasion resistance, and skid resistance were measured. The results show that more than 40% of sand replacement with waste materials could have a negative effect on the properties of RCCPs. However, this impact is negligible up to 10% of waste material proportions. The compressive strength of the mixes containing waste materials was lower than that of the control mix, except for the sample containing 10% ceramic waste. In terms of water absorption, mixes with waste materials had higher water absorption than the control mix. Besides, abrasion somewhat increased as a result of adding waste materials, except for the samples containing 10% glass and 10% ceramic wastes that showed a slight decrease. Moreover, mixes with waste materials had higher skid resistance than the control mix. Overall, waste ceramic mixes showed better mechanical properties and waste glass mixes had better performance in terms of water absorption. In addition, using nano SiO 2 leads to improve the mechanical properties of the RCCP; the optimum content of nano SiO 2 has determined to be 0.7% of cement weight.

During the last three decades, concrete pavement or rigid pavement became a widely used alternative of flexible pavement (asphalt pavement) at freeways and highways with high traffic of heavy vehicles, due to its durability, long life, and less need of maintenance; however, the cost of construction for rigid pavement is very high compared to asphalt pavement. Developing a new concrete mixture to increase the performance and reducing the required thickness of concrete pavement became an important issue in rigid pavement design in order to reduce the high construction cost. In this study, a new concrete mixture was developed using specific amounts of steel fibers and steel slag (as a supplementary cementing material to replace a part of the cement). Several mixtures with different concentrations of fibers were prepared, and samples were tested for workability, early flexural strength, and ultimate flexural strength. e results showed that the new concrete mixture could achieve an increase in flexural strength between 48.9% and 50.5% compared to normal concrete mixture without steel fibers and steel slag, with minimum acceptable workability, and therefore, the required pavement thickness could be decreased by more than 24%.

Effect of glass grid as high tensile strength layer in rigid pavements /runways has been studies using model slabs of low slump value and high strength concrete M40 (40N/mm2) with flexural strength of 4.4 N/ mm2,desighned for 1800kg gross load with 1200 repetition casted over the same sub grade on which runways was to be reconstructed .The slabs after subjected to loads shows that there occurs least number of cracks with less width and propagate to lesser depths and non – continues in nature by the use of glass grids as secondary reinforcement also there is considerable arrest of reflective cracks in case of
rigid overlays over cracked pavement.

Cooperation between layers represents one of the current issues regarding road pavements analysis on their operational behavior by traffic loads. The bond between road layers, by most of calculation methods, including the Romanian ones,is considered perfect. It is hard to say how true this statement is, but it is expected the fact that it is unlikely for this bond to be “perfect” for the entire service life of the road pavement. A road pavement is calculated depending on a certain number of parameters (traffic, bearing capacity of foundation soil, the characteristics of materials in road pavement composition etc.) so that each road layer will only be loaded on its own level of bearing capacity. Specific stresses and strains are transmitted in different layers depending on the characteristics of component materials and the bond between them. The paper aims to examine the hypothesis of the bounding between road layers on numerical modeling with ABAQUS 6.8-3, a commercial modeling program, based on finite element method that was widely applied in road pavements analysis. Thus, two road complexes were studied (flexible road pavement, mixed road pavement) and resulted states of strains in different analysis hypothesis.

Since recent times the reliance on sustainable engineering options has increased to a great extent. In road construction also rigid pavements offer the most preferred option to choose for as they are long lasting, almost maintenance free and have better riding quality. Thickness of the concrete pavement depends mainly on the subgrade strength, axle load repetitions, type of sub-base, type of shoulders, whether the pavement layer is bonded with the dry lean concrete subbase or not and temperature variation. A small decrease in the thickness of the pavement will result in saving the material to a large extent over the course of hundreds of kilometres of a road. This paper presents the results of the design of a rigid pavement for a NH assumed to be provided in Haryana for the two cases (i) when pavement is designed as a conventional pavement, and (ii) when pavement is designed as a bonded concrete pavement wherein separation membrane between dry lean concrete subbase and cement concrete slab is eliminated. The pavement is provided with dowel and tie bars. The design of the pavement has been carried out as per IRC:58-2015. It is observed from the design that a reduction in the thickness of pavement of about 20% can be achieved by adopting the concept of bonded rigid pavements. The saving in the thickness of the pavement and hence the materials to be used can help attaining the goals of sustainable development in an effective manner.

The evaluation of soil reaction in geotechnical foundation systems such as concrete pavements, mat-and raft foundations is a challenging task, as the process involves both the selection of a representative mechanical model (e.g., Winkler, Continuum, Pasternak, etc.) and identify its prevailing parameters. Moreover, the support characteristics may change with time and environmental situation. This paper presents a new method for the characterization of plate foundation support using high-resolution fiber-optic distributed strain sensing. The approach involves tracking the location of distinct points of zero and maximum strains, and relating the shift in their location to the changes in soil reaction. The approach may allow the determination of the most suited mechanical model of soil representation as well as model parameters. Routine monitoring using this approach may help to asses the degradation of the subsoil with time as part of structural health monitoring strategies. In this paper, fundamental expressions that relate between the location of distinct strain points and the variation of soil parameters were developed based on various analytical foundation support models. Finally, as an initial validation step and to underpin the idea basics, the proposed method was successfully demonstrated on a simple mechanical setup. It is shown that the approach allows for load-independent characterization of the soil response and, in that sense, it is superior to common identification methods.