Pavement Model Research Articles

Finite element analysis of GFRP reinforced concrete pavement under static load

GFRP was more corrosion resistant than traditional reinforced, it is lightweight, high strength thermal expansion coefficient is more close to the concrete and a poor conductor of electromagnetic. Therefore, the use of GFRP to replace the traditional reinforcement in concrete pavement application has excellent practical value. This paper uses ANSYS to establish delamination and reinforcement of Pavement model and analyzed response of GFRP concrete and ordinary concrete pavement structural mechanics on effects of different factors under the action of static. The results showed that under static load, pavement surface layer presented similar changes on stress of surface layer, vertical and horizontal deformation in two kinds of pavement structure, but indicators of GFRP reinforced concrete pavement were obviously better than that of ordinary concrete pavement.

Continuous strain monitoring of an instrumented pavement section

ABSTRACTClassically, measurements on instrumented pavements are performed on site, under known load conditions. In such conditions, data interpretation and modelling of the pavement are relatively easy. However, on-site measurements are time consuming and costly to perform, because they require using a dedicated vehicle and closing the lane to traffic. This paper presents an experiment, where an instrumented bituminous pavement motorway section has been followed by remote monitoring, under normal traffic. The section, instrumented with strain gages, temperature probes and geophones, has been monitored continuously during 18 months. Signal sorting procedures have been developed for reducing the quantity of recorded data, and for analysing the structural response of the pavement, under highly variable loading conditions. The results of the strain gage measurements, made at different depths within the pavement, have shown that the response of the pavement presents large variations with temperature, and in particular, that the degree of bonding between layers can decreases at high temperatures, leading to sliding between pavement layers. The mechanical response of this section has been analysed using a classical multi-layer linear elastic pavement model and also a viscoelastic model. The best predictions have been achieved with the viscoelastic model. Different approaches for describing the behaviour of pavement layer interfaces have also been evaluated.

Temperature prediction model for flexible pavements at various depths for the States of Arizona and Minnesota

Temperature variation significantly influences the selection of the asphalt binder grade. Also, since that the asphalt is a viscoelastic material, the critical responses such as surface deflection and stiffness of the asphalt layer will be highly affected by any temperature change. Most of the methods employed by transportation agencies to measure pavement temperature at present involve drilling a bore hole; therefore, generating a hazard that may cause pavement deterioration. A simple and non-destructive method to predict the pavement temperature is one of the important requirements for pavement engineers. This study created a model that can predict the pavement temperature at various depths utilising basic climatic parameters such as air temperature, pavement surface temperature, relative humidity, and precipitation. Required data were extracted from an open source online database and the two generated models for the state of Minnesota and the state of Arizona were reliable with an acceptable coefficient of determination value.

Temperature prediction model for flexible pavements at various depths for the States of Arizona and Minnesota

Temperature variation significantly influences the selection of the asphalt binder grade. Also, since that the asphalt is a viscoelastic material, the critical responses such as surface deflection and stiffness of the asphalt layer will be highly affected by any temperature change. Most of the methods employed by transportation agencies to measure pavement temperature at present involve drilling a bore hole; therefore, generating a hazard that may cause pavement deterioration. A simple and non-destructive method to predict the pavement temperature is one of the important requirements for pavement engineers. This study created a model that can predict the pavement temperature at various depths utilising basic climatic parameters such as air temperature, pavement surface temperature, relative humidity, and precipitation. Required data were extracted from an open source online database and the two generated models for the state of Minnesota and the state of Arizona were reliable with an acceptable coefficient of determination value.

A Large‐Scale Test Method for Mechanical Response of Pavement Structure

A test method for mechanical response of pavement structure with the large scale model was presented in the study. The strain was tested on three large scale models of pavement structure with three typical pavement materials of cement concrete (CC), cement stabilized macadam (CSM) and asphalt concrete (AC) under the different load levels. Theoretical calculations of the strain on the top surface of CC, CSM and AC pavement models were also developed by BISAR3.0, which is a software for mechanical analysis based on elastic layered system. The research results indicate that the test method for mechanical response of pavement structure with large scale model presented in the study shows a low variability, and a good repeatability and reliability, which can be used as an effective way to study the mechanical response of pavement structure instead of full‐scale test. The research results can provide some references for theoretical calculation of pavement structure and determination of pavement material parameters.

Development of HPCI Prediction Model for Concrete Pavement Using Expressway PMS Database

Development of HPCI Prediction Model for Concrete Pavement Using Expressway PMS Database

Pavement Temperature Prediction Model for Oman Climate Condition

Asphalt pavement is form an integral part of any transportation system. Temperature is the significant factor that effect on the performance and life span of a pavement. This paper study the relationship between the air temperature and asphalt pavement temperature and using Excel in order to predicate surface asphalt pavement model for Muscat climate. The models were compared with the standard models SHRP and LTPP models [3]. The development models resulted the surface pavement temperature was taken more time in heating cycle than air temperature. When compared the air temperature and surface asphalt pavement temperature with the standards models SHRP and LTPP models. There was difference between them due to the standards models was design for low temperature under zero where in Muscat temperature cannot be under zero [2].

Dobór obszaru i warunków brzegowych modelu nawierzchni drogowej podatnej w analizie metodą elementów skończonych

The paper presents three methods for defining a finite cylindrical-type domain for finite element analysis of an elastic multi-layered half-space subjected to a rotationally symmetric vertical load distributed over a circular area, thus providing a mechanistic model of a flexible road pavement. For three sets of boundary conditions the methods ensure the consistency between the maximum deflection and the exact calculated value for a multi-layered half-space with compromising the accuracy of the key strain values. The first case uses standard support conditions at the finite element model boundaries – fixed in the direction perpendicular to that plane and sliding in the tangential direction. The other two cases use half-infinite elements – at the base and at the side wall of the domain. The first method, as an additional benefit, enables determining the exact value of the maximum deflection of pavement that can be used in the second and in the third of the described methods.

The modelling prediction of haul road surface deflection

Abstract Haul road pavement design is often completed through application of axisymmetric linear-elastic modelling. This may be implemented either through the derivation of cover curves employing the California Bearing Ratio, or within linear-elastic modelling completed by commercially available software. In recent years, a significant amount of research has been conducted on the application of the Finite Element Method for the analysis of pavements. A study to determine the accuracy of predicted haul road pavement response made by various linear-elastic and Finite Element Methods was undertaken. The deflected pavement surface profile was measured for three haul road pavement sections utilising terrestrial laser scanning, which also allowed measurement of the tyre/pavement contact geometry. Laboratory testing was completed to define the stiffness of each material through triaxial testing. Results of the field and laboratory testing allowed modelling via each method. Only minor variations were observed between the various linear-elastic modelling approaches that were investigated. In general, the Finite Element Method was found to produce the most accurate predictions. These findings provide the impetus for further investigation and the use of Finite Element Method for haul road pavement modelling.

Viscoelastic Asphalt Pavement Simulations and Simplified Elastic Pavement Models Based on an “Equivalent Asphalt Modulus” Concept

Abstract Asphalt pavements exhibit viscoelastic behavior resulting in deflections, strains, and stresses varying with both temperature and traffic speed. For structural thickness design against fatigue cracking, the material response is typically assumed to be linear elastic to simplify the calculation of the critical horizontal strain at the bottom of the asphalt layer. An asphalt modulus representing the response of the materials under average conditions for both temperature and traffic speed is generally adopted in the simplified pavement model. This paper presents a method to determine an equivalent asphalt modulus (EAM) for the asphalt layer. The EAM, when used in the linear elastic analysis of a pavement, will result in a resilient response in terms of the critical strain criterion that is equivalent to the response of that structure when calculated using viscoelastic modeling. The methodology of this paper included a qualitative comparison of the EAM approach with published field results. Two thick asphalt pavement configurations representative of typical French pavement designs were considered in this paper. Results showed expected trends of the equivalent asphalt modulus with changes in traffic speed and temperature. The application of time–temperature superposition principle allowed building pseudo-master curves for the EAM dataset. The effect of different asphalt temperature and different traffic speed on the viscoelastic strains was qualitatively validated against the trends observed under full-scale testing.

Path tracking control for inverse problem of vehicle handling dynamics

A path tracking controller based on active disturbance rejection control(ADRC) theory is presented in this paper to solve path tracking problem in inverse vehicle handling dynamics. The basic idea behind the work is to design an active disturbance rejection controller according to yaw rate and lateral displacement during a vehicle travels along a prescribed path to generate an expected trajectory which guarantees minimum clearance to the prescribed path. Aiming at this purpose, using preview follower theory, a linear extended state observer based on lateral displacement is designed. Considering yaw angle of vehicle, a non-linear combination function combined error of lateral displacement as well as error of yaw angle is designed according to monotone bounded hyperbolic of tangent function. Finally, a real vehicle test is executed to verify the rationality of the path tracking controller. At the same time, according to characteristics of pavement file in Carsim, a 3-D virtual pavement model is established and ride comfort simulation of random pavement is carried out in the software model. The results show that the minimum lateral position error of the generated path tracking trajectory can be good indicators of successful solving of the path tracking problem in inverse vehicle handling dynamics for ADRC. More precisely, there is higher calculation accuracy for the algorithm of the ADRC to solve the path tracking problem. The study can help drivers easily identify safe lane-keeping trajectories and area.

An innovative Primary Surface Profile-based three-dimensional pavement distress data filtering approach for optical instruments and tilted pavement model-related noise reduction

The automatic pavement management system has the advantage of providing reliable pavement maintenance and rehabilitation strategies aiming at prolonging existing pavement service life. Therefore, the quality of noise reduction results, which is an unavoidable process of automatic pavement assessment evaluation, has a significant influence on the reliability of pavement maintenance operations suggested. The primary purpose of this paper is to propose an innovative three-dimensional (3D) pavement image-based data filtering protocol, thereby maintaining a highly functional pavement surface. First, a 3D pavement depth data collection system was developed using laser light and a charge-coupled device camera. After that, based on the analysis of Positive Noise and Negative Noise, which are optical instrument-related noises, and tilted pavement model noise, the Primary Surface Profile (PSP)-based raw data filtering approach was proposed which aims at improving the noise reduction quality. Validation experiments were conducted using both the proposed approach and the traditional data filtering method, and the results show that for the not tilted pavement surface model, the PSP-based filter method can achieve the highest noise reduction value (NRV), whereas for the tilted pavement surface model, with a slightly lower NRV than that of biphasic standard deviation average filtering, which demonstrates that the proposed data filtering method has self-adaptive and robust data filter advantages which can be incorporated into a high-performance pavement performance evaluation and management system.

The effect of wetting and drying on the performance of stabilized subgrade soils

Abstract Stabilization methods are often utilized to improve the performance of road pavement subgrades which are weak or susceptible to small changes in moisture content. However, although a variety of performance models for natural materials have been developed and incorporated within road pavement design methodologies little research attention has been given to the characterization of similar performance models for stabilized subgrade soils. To address this, the research reported herein describes and discusses the results of a laboratory testing programme, incorporating cycles of wetting and drying, for a number of stabilized subgrade soils to determine the resilient behaviour and permanent deformation characteristics of the soils. The results from the experiments were used to characterise six models of subgrade soil permanent deformation performance identified from the literature and from these to develop a new improved model of performance which incorporates resilient behaviour. A comparison of the existing models of permanent deformation showed that those which consider stress state in addition to the number of load repetitions are better able to predict permanent deformation than those which consider the number of load cycles only. Samples subject to wetting and drying exhibited significantly greater permanent deformation and had lower values of resilient modulus than those which were not subject to wetting and drying. The usefulness of the results for analytical road pavement design are demonstrated by using a back-analysis procedure to determine appropriate resilient modulus values to characterise an analytical model of a road pavement together with the performance models to predict road pavement subgrade performance under cumulative applications of traffic load. Accordingly, the results show the importance of adequately replicating material behaviour in field conditions. In particular, the design process must utilize resilient modules values and deformation models which are determined in conditions which take into account in-situ stresses and cycles of wetting and drying.

Application of Dynamic Analysis in Semi-Analytical Finite Element Method.

Analyses of dynamic responses are significantly important for the design, maintenance and rehabilitation of asphalt pavement. In order to evaluate the dynamic responses of asphalt pavement under moving loads, a specific computational program, SAFEM, was developed based on a semi-analytical finite element method. This method is three-dimensional and only requires a two-dimensional FE discretization by incorporating Fourier series in the third dimension. In this paper, the algorithm to apply the dynamic analysis to SAFEM was introduced in detail. Asphalt pavement models under moving loads were built in the SAFEM and commercial finite element software ABAQUS to verify the accuracy and efficiency of the SAFEM. The verification shows that the computational accuracy of SAFEM is high enough and its computational time is much shorter than ABAQUS. Moreover, experimental verification was carried out and the prediction derived from SAFEM is consistent with the measurement. Therefore, the SAFEM is feasible to reliably predict the dynamic response of asphalt pavement under moving loads, thus proving beneficial to road administration in assessing the pavement’s state.

Mechanism Analysis of the Use of LSPM for Reflection Crack Prevention of Semi-Rigid Base Asphalt Mixture

The damage mechanism of reflective cracking, particularly on semi-rigid asphalt pavement with large stone porous asphalt mixture (LSPM) is investigated in this study.An asphalt pavement model with multilayered base (i.e., LSPM and semi-rigid layer) using discrete element methodis developed.This study analyzes the influence of the inner structure of asphalt mixture on the stress field around the crack tip, which is under the vehicle load after the cracking of a semi-rigid layer. The focus is on the mechanism of cracking and the influence of the inner structure of the mixture, such as gradation, the geometric feature of coarse aggregate, and space.The crack expansion rate is also analyzed.Results show that, under vehicle load, the crack in the semi-rigid layer causes stress concentration, which decreases around the bottom of the LSPM.The load on the top of the crack tip produces stress level concentration, the unbalanced load produces shear stress concentration, and the stress decreases progressively from the crack tip to the surrounding area. In the LSPM, a large grain size of the coarse aggregate is better than a small grain size. Its overall stress level is low and the crack development rate is slow on the stress field of the crack tip. The LSPM can reduce stress concentration and prevent the development of reflective cracking effect.

Correlation between pavement temperature and deflection basin form factors of asphalt pavement

ABSTRACTIn this study, the effect produced by pavement temperature change on asphalt pavement deflection basin form factor was studied. To determine the correlation between temperature and deflection basin factors of asphalt pavement, deflection tests were carried out on three roads with various thicknesses at different temperatures in one-year cycle. The air temperature and pavement temperature at different depths of the pavement were also measured during falling weight deflectometer testing. First, based on the experimental results and also by taking into account the difference between heating and cooling cycles of the air, a temperature model of asphalt pavement was developed to determine the pavement temperature. Then the relationship between the maximum deflection value and pavement temperature as well as the temperature correction relations was established through regression analysis. Finally, the relationship between the other deflection basin form factors and the pavement temperature was analysed. The results demonstrate that the pavement temperature prediction model is simple yet highly accurate, indicating the inherent correlation between the deflection basin correction factors and pavement temperature. The temperature correction relations of deflection basin factors built in this study are accurate and reasonable, which would be helpful for quality testing and modulus back-calculation of asphalt pavement.

Time-frequency analysis of air-coupled GPR data for identification of delamination between pavement layers

Identification of delamination in pavement layers using ground penetrating radar (GPR) is still challenging due to its limited range resolution. This paper investigates the characteristics of the composite reflection from the air-filled delamination between pavement layers by time-frequency analysis. We firstly simulated GPR data from an asphalt pavement model with an embedded air gap of different thicknesses by the Green’s function method. Then we conducted a laboratory experiment on a delaminated asphalt pavement model. Both the numerical and laboratory experiment results demonstrate that both the peak instantaneous frequency and its amplitude are sensitive to the variation of the air gap thickness. When the thickness of the air gap is smaller than a quarter of the dominant wavelength, the peak instantaneous frequency of the composite reflection is higher than that of the normal interface reflection. We conclude that we can identify the delamination from the overall rise in the peak instantaneous frequency.

Application of mechanical and electromagnetic waves in an integrated determination of pavement bearing capacity

The use of expert systems to determine pavement fatigue life (such as backcalculation) is strongly constrained by empirical assumptions. An important obstacle for the development of this research area is a conflict between the complexity of pavement model and actual limitations of methods used to identify its parameters. This article describes the original concept of device, which combines advantages of different methods of testing the pavement needed to calculate its fatigue life. Combined methods are based on the theory of propagation of both mechanical waves and electromagnetic waves in the layered pavement medium. The proposed hybrid solution is the starting point for the development of an expert system based on semi-invasive and non-invasive methods of obtaining the calculation values for parameters of pavement layers. It is believed that backcalculation results based on such identification are characterized by lower uncertainty comparing to the standard approach. As a consequence, the precision of overlay design for pavements will be increased.

Stress, Strain-Rate Analysis of Sub-Surface Driveway Plants

Sub-surface driveway plants are strong enough to penetrate a macadam surface of thickness 7 – 9 cm. The mechanics of how the Taraxacum officinale accomplishes this feat remain a mystery. Using the Maxwell model for pavement yielding over time, data are presented which may shed some light on this phenomenon. The post-buckling behavior of the plant stalk is quantified. Euler bending and buckling theory enables calculation of the cellular stress field, compared to turgor pressure, indicating impending cell buckling. Post-buckling plastic strain of the plant stem is 19%. At the cell wall, the stress concentration factor is 3-times greater than the applied external field, so the cell’s internal turgor pressure is overwhelmed by imposed external stress. An Impulse Integral is developed for the surface whereby the product of applied FORCE times TIME is CONSTANT, in order to produce a given amount of surface deflection. Taraxacum officinale stems and leaf stalks are strong enough, in buckling mode, to lift and push apart the fractured macadam crater through which they erupt, but not strong enough to initially crack the surface. The purpose of this work is to determine the mechanisms underlying this unusual plant survival phenomenon, backed by quantified data.

Application of Finite Layer Method in Pavement Structural Analysis

The finite element (FE) method has been widely used in predicting the structural responses of asphalt pavements. However, the three-dimensional (3D) modeling in general-purpose FE software systems such as ABAQUS requires extensive computations and is relatively time-consuming. To address this issue, a specific computational code EasyFEM was developed based on the finite layer method (FLM) for analyzing structural responses of asphalt pavements under a static load. Basically, it is a 3D FE code that requires only a one-dimensional (1D) mesh by incorporating analytical methods and using Fourier series in the other two dimensions, which can significantly reduce the computational time and required resources due to the easy implementation of parallel computing technology. Moreover, a newly-developed Element Energy Projection (EEP) method for super-convergent calculations was implemented in EasyFEM to improve the accuracy of solutions for strains and stresses over the whole pavement model. The accuracy of the program is verified by comparing it with results from BISAR and ABAQUS for a typical asphalt pavement structure. The results show that the predicted responses from ABAQUS and EasyFEM are in good agreement with each other. The EasyFEM with the EEP post-processing technique converges faster compared with the results derived from ordinary EasyFEM applications, which proves that the EEP technique can improve the accuracy of strains and stresses from EasyFEM. In summary, the EasyFEM has a potential to provide a flexible and robust platform for the numerical simulation of asphalt pavements and can easily be post-processed with the EEP technique to enhance its advantages.