Rigid Pavement Slabs Research Articles

Studying the Impact of Soil Stabilization Techniques on Rigid Pavement Joints Across Various Axle Loads

Rigid pavement slabs are erected on a prepared subgrade or foundation layer, providing a hard and continuous surface. Transverse joints made of dowel bars connect them, and longitudinal joints made of tie bars join them longitudinally. This study is an investigation of the impact of soil strength and concrete parameters on the effectiveness of dowel bars in rigid pavements. Moreover, three parameters were examined; California Bearing Ratio (CBR), concrete compressive strength and slab thickness. The analysis was conducted using the Ever FE program and focused on several axle configurations applied to the joint. The results indicate inverse association between the pavement slab thickness and the concrete strength, under the assumption of consistent soil strength. Moreover, an assortment of reduced shear forces on the dowel bars is seen when the soil strength values increase. It indicates that soil strength has a greater impact on the shear load of dowel bars compared to the qualities of concrete. Additionally, the type of axles used and the magnitude of soil strength were shown to have a significant effect on the shear load.

Development of temperature differential maps for rigid pavements in tropical climates for quick estimation of thermal stresses

ABSTRACT Accurate estimation of the thermal stresses in rigid pavements is essential for the assessment of its service life. Thermal stress (an outcome of temperature differential) within the slab is significantly dependent on local weather conditions. This article presents a methodology for prediction of temperature profiles in rigid pavement. In this work, partial differential equations governing heat transfer through concrete pavement are numerically solved. The boundary conditions of the heat transfer model were formulated based on the real-time weather data. The temperature profiles predicted by solving the model were used to calculate the temperature difference between the top and bottom of the rigid pavement slab. The proposed methodology was implemented using 30 years of gridded weather data for whole of India. From the predicted temperature profiles, the annual M P T D and M N T D of the pavement slab were calculated. The mean values for each grid point observed over 30 years were used to develop temperature differential maps. The predicted values of maximum positive and negative temperature differentials had significantly higher values compared to the current codal recommendations of India. Developed maps can be used for estimating the design temperature differentials in places having similar climatic conditions presented in this study. Abbreviations: DLC: dry lean concrete; GSB: granular subbase; IRC: Indian Road Congress; MMMT: mean monthly maximum temperature; MMRH: mean monthly relative humidity; MTD: maximum temperature differential; MPTD: maximum positive temperature differential; MNTD: maximum negative temperature differential; PDE: partial differential equation; PQC: pavement quality concrete; SG: subgrade; TD: temperature differential

Feasibility study of calculation methods for tram track stiffness

Nowadays, design and construction of new urban tramlines require feasibility study of calculation methods for stiffness. A calculation method for tram track stiffness with noise and vibration insulation systems has been developed in this paper. Theoretical analysis of the impact of rail insulation systems on tram-to-slab load transfer has revealed the potential options and factors influencing the choice of a system. The new design method obtained makes it possible to predict the distribution of loads on the load-bearing foundation surface. Different variants of rail/slab load distribution have been determined depending on the mechanical characteristics of rail profiles. Tram track slab stiffness has been calculated for three design models such as rigid surface pavement, bridge structure and foundation slab. The design of the tram track as foundation slab allows calculating slab reinforcement as accurately as possible because the surface pavement takes into account the planned service life and tram flow density in the area under survey.Field experiments have demonstrated a better convergence of theoretical and experimental data when designing the slab as foundation. As a result, a new method for calculating the foundation slab stiffness of a tram track has been proposed taking into account planned service life, tram flow density and other factors.

Critical stress evaluation of rigid pavement due to the presence of water in expansive soil subgrade

The use of various types of rigid pavement is widespread because of its superiority in resisting heavy load vehicles. However, traffic loading complexity and subgrade response cause uncertainty during the design process. The presence of water in expansive soil issue swelling affected the flexural behavior of a rigid pavement slab. Rigid pavement relies heavily on the support and stability of the subgrade. Plain concrete is very weak in resisting tensile stresses so that the failure of rigid pavement slab structures often occurs in the expansive subgrade zone. Therefore, this study aims to numerically analyze the relationship between variations in the thickness of rigid pavement slabs on the flexural behavior parameters, such as critical and tensile stresses that affected water in expansive soil. The concrete’s performance limit was determined, using its material’s constitutive equation curve, and the data were analyzed using the finite element method. The results showed that the presence of water in expansive soil caused a change in soil volume (swelling), a reduction in soil bearing capacity (shrinking), and consequently, a rigid pavement cracked due to water variations in the subgrade. Generally, increasing the thickness of rigid pavement is a common method for mitigating the detrimental effects of expansive soil swelling. It is possible to provide reinforcement in other forms, which provide an opportunity to improve the performance of the concrete slab as a rigid pavement. For example, stabilization of expansive soil with materials capable of reducing its expansive power can be done but it requires large resources to realize it. Another method is to provide reinforcement to the rigid pavement slab structure, so that the rigid pavement slab is able to withstand traffic loads and also the expansion and shrinkage behavior of the expansive soil

Evaluation of the Incorporation of Tire-Derived Aggregates (TDA) in Rigid Pavement Mix Designs

Owing to the extensive worldwide generation of solid wastes, such as rubber tires, and the resulting adverse environmental impacts, the incorporation of these waste materials in construction projects has become a widespread aim. However, concerns have arisen regarding the effects of rubber waste on the mechanical properties of Portland cement concrete (PCC) mixes. Thus, this study investigates the effects of replacing natural coarse aggregates with tire-derived aggregates (TDA). In PCC mixes, natural aggregates were replaced by 0, 10, 20, 40, 60, 80, and 100% TDA by volume, and the properties of these specimens were tested in the laboratory. The results obtained were then used as inputs for the KENPAVE software, to evaluate induced stresses, deflections, and cracking indices in rigid pavement slabs, with eleven different thicknesses, ranging from 200 to 300 mm in 10 mm increments. Stresses under different loading conditions decreased as PCC slab thickness and TDA content increased. Increased deflection and cracking indices resulting from adding TDA could be counteracted by increasing the PCC slab thickness by 10 mm. Moreover, environmental impacts and cost analyses were examined via PaLATE 2.0, which showed that the use of TDA could reduce energy consumption, harmful emissions, and material costs. Overall, this study indicates that the use of TDA in PCC mixes has benefits that can make it a good candidate for sustainable, ecofriendly rigid pavement construction projects.

Experimental and Numerical Investigation of Load-Carrying Capacity of Rigid Pavement Slabs Reinforced with Biaxial Geogrid

Experimental and Numerical Investigation of Load-Carrying Capacity of Rigid Pavement Slabs Reinforced with Biaxial Geogrid

Condition assessment of rigid pavement using terrestrial laser scanner observations

ABSTRACT The main task of this study is to introduce an applied methodology using terrestrial laser scanner for facilitating the process of detecting, measuring defects and evaluating the condition assessment of rigid pavement instead of traditional visual inspection methods which cause waste of time, high cost and work to disrupt traffic. Terrestrial laser scanner (TLS) was used to create a three-dimensional model for rigid pavement of Gas station in Kafr El-sheikh city in Egypt to evaluate the condition assessment and defect detecting. The evaluation was carried out on rigid pavement slabs with different distress types such as transverse cracking, joint spalling, polished aggregate, blow up, punch out failures, and surface defects. Pavement distresses were identified in terms of defected area, crack width, and intensity. Geometric properties of each rigid pavements slabs are also determined from terrestrial laser scanner observations such as dimensions, settlement of each rigid slab using plane equation technique, rotation and tilting angles for each slab. MAGNET COLLAGE software program was applied to process TLS data and surface cracks measuring. Designed MATLAB software program are also created to fit TLS observations to plane equations. Based on the results, it is deduced that the distortion of rigid slabs ranged from 10 to 46 mm as maximum values and from 1 to 5 mm as minimum values, the angles of the rotation of studied rigid pavement slabs ranged from 0° to 2.3° but the angles of tilting of studied rigid pavement slabs are ranged from −1.6° to 1.9°. The revealed defects in the studied Gas station using terrestrial laser scanner observations provide a significant improvement for detecting rigid pavements characteristics and distresses.

ANALYSIS OF THE EFFECT OF SLAB THICKNESS ON CRACK WIDTH IN RIGID PAVEMENT SLABS

Cracks that occur in rigid pavements include longitudinal cracks, transverse cracks, and corner cracks. The relatively large crack width not only spoils the aesthetics of the concrete structural elements but can also lead to structural failure. This study aims to determine the crack width of a rigid pavement concrete slab located above the subgrade which is considered a beam on an elastic foundation, so that a minimum rigid pavement concrete slab thickness can be recommended. The specimen will be observed at various thicknesses to obtain the optimum thickness. The load used is a centralized monotonous load, which represents the load of the truck vehicle. The research limitation is using a test object in the form of a concrete plate measuring 2000x600 mm which is placed on the ground with CBR=6 %. The quality of reinforced concrete slabs is fc'=40 MPa and fy=440.31 MPa. The thickness of the concrete slab varies between 100 mm, 150 mm, and 200 mm. The slab placed on the ground is then given a central loading in the form of a centralized monotonic load. The loading range starts from a load of 2–180 kN with a load interval of 2 kN. The experimental results show that the rigid pavement slab has a bending failure so that the crack pattern that occurs begins with the first crack on the underside of the slab. The crack pattern in terms of slab thickness variation has a similar pattern. The initial crack width on the slab is 0.04 mm. The thicker the slab smaller the crack width at the same load. Based on the maximum allowable crack width=0.3 mm. For loads between (80–100) kN (Road Class I, II, and III), a minimum thickness of rigid pavement slabs (70–80) mm is recommended. For loads between (130–140) kN, the minimum thickness of the rigid pavement slab (105–115) mm is recommended

Effect of metakaolin-based geopolymer concrete on the length of rigid pavement slabs

Rigid pavement is one of the pavement methods used specially in high traffic zones. Up till now, Portland cement concrete (PCC) is the most commonly used material for rigid pavement. One of the problems that faces PCC is the allowable spacing for transverse joints in rigid pavements’ plain concrete slabs. As recommended by different standards and design manuals, the recommended length of slabs is about 4.5–5 m (In PCA, Thickness Design for Concrete Highway and Street Pavements. Engineering Bulletin EB109P. Skokie, IL, (1984); In ECP, Egyptian code of practice for urban and rural roads part 4: road material and its tests. Housing and Building National Research Center, Egypt, (2018); In FDOT, Rigid Pavement Design Manual. Pavement Management Office, Document No. 625-010-006-e, Tallahassee, Florida, (2009)), this is referred to the thermal volumetric changes in PCC. The low allowable transverse joints spacing in rigid pavement reduces the implementation rates and increases the cost. Geopolymer concrete (GPC) is one of the innovative types of concrete that is eco-friendly than gain early strength in ambient temperature and can gain higher strength by heating. In this research, GPC was investigated to determine its drying shrinkage and thermal expansion behavior and therefore affect the length of concrete slabs in rigid pavement. This different type of concrete showed an acceptable performance against drying shrinkage and thermal expansion more than PCC.

Determination of Stresses and Displacements in Rigid Pavement Slabs, Through Finite Element Analysis

Determination of Stresses and Displacements in Rigid Pavement Slabs, Through Finite Element Analysis

Evaluation of the structural capacity of rigid pavements at the network level

Pavement surface deflection has been used by researchers and highway agencies to assess the structural condition of the pavement structure. None of the currently available approaches provides an acceptable evaluation method for the rigid pavement structural capacity at the network level. In this research, pavement structural ratio (PSR) and overall pavement structural index (OPSI) were derived from deflection bowls generated from finite element simulations and validated by actual field deflection data measured by falling weight deflectometer and performance data extracted from long-term pavement performance database. The PSR parameter provides structural evaluation of the rigid pavement slab and the base course above the subgrade only. Whereas, OPSI parameter provides an overall evaluation of the pavement structure and the subgrade.

Studies on Green Concrete Pavement: Experimental and SVM Modelling

In this study, the thickness of the rigid pavement slab is optimized by replacing cement with Ground Granulated Blast Furnace Slag (GGBFS) and Polypropylene (PP) fibers. In this regard, the flexural strength of concrete samples is studied with 40, and 50% GGBFS and 0.2 to 0.6 % PP-fibers. From the results, it is observed that the flexural strength of concrete with 50% GGBFS yields higher strength and with PP fibers improves the crack resistance. Later from the obtained experimental data, the support vector machines (SVM) with different kernel functions are developed to predict the flexural strength of concrete. The SVM model shows a good correlation with the experimental data regarding the correlation coefficient (CC) and root mean square error (RMSE). SVM with a spline kernel yields good prediction for both flexural strength of concrete with CC of 0.9996 and 0.9756, RMSE of 0.0070 and 0.0554 for training and testing respectively. From the results, it can be concluded that GGBFS and PP fiber could be used as alternative materials to reduce the carbon footprint and SVM as an alternative tool to predict the flexural strength of concrete.

Fortification of Damaged Asphalt Pavements with Cement Concrete Slabs Reinforced with Next-Gen Bars – Part I: Laboratory Study

AbstractOver the course of operation, asphalt road pavements are subjected to damage from car traffic loads and environmental factors. One of the possible methods of strengthening damaged asphalt pavements may be the application of an additional rigid layer in the form of a cement concrete slab with continuous reinforcement.This paper presents a material-technological and structural solution for composite pavement where a cement concrete slab with continuous HFRP bar reinforcement is used for strengthening. Based on laboratory tests, the serviceability of composite bar reinforcement of rigid pavement slabs was shown. A design for strengthening asphalt pavement with a concrete slab with steel bar and corresponding HFRP bar reinforcement was developed. The composition of a pavement cement concrete mix was designed, and experimental sections were formed. Based on laboratory tests of samples collected from the surfaces of experimental sections and the diagnostic tests carried out in “in situ” conditions, the authors will try, in the nearest future (Part II: In situ observations and tests), to confirm the effectiveness of strengthening asphalt pavements with cement concrete slabs with HFRP components.

RETRACTED: A developed method of analyzing temperature and moisture profiles in rigid pavement slabs

This study proposes a developed method to compute the temperature and moisture distribution along the depth of the rigid pavement slab via a one-dimensional heat and moisture transfer model using Crank-Nicolson finite difference method. The components of thermal conductivity (K) and moisture diffusivity (D) are added to the existing numerical model, and their effects are evaluated by comparing numerical results with field measurements via an ATEK Concrete Maturity Meter (ACMM) system. The results section presents from the following aspects: (1) the impacts of coupling effect of temperature and moisture on pavement temperature and moisture distribution along the slabs at early age, (2) the feasibility of using thermal conductivity (K) and moisture diffusivity (D) in the developed numerical model, and (3) the goodness of fitting between the predicted and measured temperature and moisture values. The subsequent discussion concentrates on whether the predicted results of the numerical model can be used to develop similar conclusions both in the laboratory and field. The discussion also focuses on the boundary-formulation differences between the proposed model and the field test model for concrete slabs, which is highlighted in terms of how these models characterize the impact of temperature and moisture profile inside of pavement slab.

The Comparison of Two Airport Rigid Pavement Load Stresses

Hankel integral transform and H.M.Westergaard are two common methods for solving the differential equation of elastic surface of airport rigid pavement slab. The influence of the pavement slab elastic modulus, the pavement slab thickness and the foundation reaction modulus to the two solving methods is studied in this paper. The results can be seen in the conclusion.

Method of Analyzing the Size of Voids Beneath Rigid Pavement Slabs

The size of voids beneath rigid pavement slabs is an important factor which influences the bearing capacity of roads. GPR is an advanced method for detecting voids beneath rigid pavement slabs. Combined with drilling and sampling, equations including parameters of GPR wave amplitude, horizontal size and vertical size of voids are established for analyzing the size of voids. Then, based on the equations, the horizontal size and vertical size of voids can be calculated according to the actual GPR wave amplitude.

Modeling temperature distribution in rigid pavement slabs: Impact of air temperature

This study presents the impact of air temperature on the temperature distributions through the depth of rigid pavement slabs. A one-dimensional heat transfer model is proposed to predict the temperature distribution across the pavement. To highlight the impact of daily temperature amplitude on a pavement temperature profiles, the summer weather condition is used as an input to simulate the temperature distributions through slabs in mountainous desert and coastal regions. The results section presents the impact of daily ambient temperature on the pavement-surface heat exchange and subsequent slab temperature development. The feasibility of using the sinusoidal-approximated air temperature is also described. The subsequent discussion concentrates on whether the predicted results of these two regions can be used to develop similar conclusions in other regions and other seasons. The discussion also focuses on the boundary-formulation differences between the proposed model and the documented temperature prediction models for concrete slabs.

Reappraisal of Recycled Concrete Aggregate as Coarse Aggregate in Concretes for Rigid Pavements

State departments of transportation began using recycled concrete aggregate (RCA) as aggregate in portland cement concrete pavement in the United States in the late 1970s. Although RCA is rarely used in current U.S. rigid pavement slabs, the impetus for its continued use remains the same: a lack of landfill space, a shortage of nearby quality natural aggregates, or both. However, as American pavement engineers and researchers place a greater emphasis on sustainable, reusable roadways, the status quo for RCA in American roadways should be reconsidered along with these new priorities. This study proposes to revisit the use of recycled concrete as aggregate in rigid pavement slabs by using overlooked research to address the concerns that prevented the wide-scale adoption of recycled concrete as an aggregate in pavement slabs by state departments of transportation. Experiences encountered in countries (mostly restricted to Europe) where the use of RCA in rigid pavement is more common are also described. New opportunities for the use of RCA as a structural component in pavement concretes are detailed.

Analysis of Damage Mechanism of Reinforced Concrete Pavement Joint Sealant

Highway agencies in Thailand select reinforced concrete pavement for highways that have to carry a high traffic volume because of the pavement's durability and ability to support heavy loads with less deformation. Joint sealant is a structural component that interconnects the pavement slabs. Limited information on the joint sealant is available in Thailand. This research proposes to analyze the damage mechanism of the joint sealant by application of the finite element method under the local environment in which it is subjected to different load patterns, temperature, and time periods. Three-dimensional finite element analysis of the joint sealant and its fatigue property are presented in this paper. Displacement of slab edge surface on both sides of the rigid pavement expansion joint by traffic loading and curling effect can cause stress and strain in the joint sealant. This study conducts an experiment to obtain the fatigue property of the joint sealant subjected to the cyclic movement induced by traffic loads and the curling effect in the rigid pavement slabs. Results of sealant behavior analysis under different configurations and damage analysis of joint sealant under fatigue loading are presented in regard to the stress–strain relation and percentage of joint sealant damage with respect to its service life. Case studies are selected to illustrate how an agency could mechanistically determine maintenance frequency of joint resealing.

Part 3: Accelerated Pavement Testing: Superaccelerated Pavement Testing on Full-Scale Concrete Slabs

Several full-scale rigid pavement slabs were constructed and tested under constant cyclic loading for fatigue. To provide the comparable maximum applied stress to number of cycles to failure (S-N) relationships for the full-scale field slabs, laboratory beam fatigue testing was conducted before field testing with the use of the same concrete mix designs. The superaccelerated pavement testing technique that was developed at the University of Texas was used in the field. The stationary dynamic deflectometer (SDD) was used to load the full-scale concrete slabs. To monitor the response of the rigid pavements, accelerometers and linear variable differential transformers were installed, and dynamic and permanent displacements of slabs were recorded during the entire testing period. All test slabs reached fatigue failure under the interior loading configuration using the SDD. This field loading system was found to be a practical and effective tool for testing the full-scale rigid pavement system. During fatigue loading, cracks began at the bottom of the slabs at the loading locations and propagated along the bottom of the slab centerline, which was the maximum stress path. Vertical crack propagation at the edge and stress redistribution occurred for the part of the slab's fatigue life. The concept of equivalent fatigue life was applied to correct the effect of the different stress ratios between the field and the laboratory testing. The laboratory beams and full-scale field slabs showed an almost identical S-N relationship after the correction for the variance of stress ratio.