Asphalt Concrete Pavement Structure Research Articles

Mechanical characteristics research of new asphalt pavement structure based on geogrid

In order to study the mechanical characteristics of new asphalt pavement structural materials, UTM testing machine and Overlay Test (OT) testing machine, four-point fatigue test, tensile test and bending strength test have been carried out on different types of grid asphalt mixtures. The result shows: the addition of different types of grids can effectively improve the mechanical properties of the asphalt concrete pavement structure; geogrid addition can improve the stress on the road surface, improve the strength of pavement materials, it can effectively alleviate early generation of fatigue cracks on the road surface; it can also effectively avoid the problem of rutting damage on the whole road surface after partial damage to the road surface; can effectively promote pavement stress dispersion, improve pavement structure stability, make the pavement structure more stable, improve its service life.

Design parameters and associated quantitative damage analyses of an asphalt concrete airfield runway

Design parameters and evaluation of associated mechanical behavior of an airfield runway asphalt concrete pavement structure is reported. French aeronautical design methodology was taken as reference. Field and laboratory procedures were employed to determine constituent materials of the designed structure. Stationary linear elastic and dynamic viscoelastic numerical damage analyses were developed and compared, using computerized tools based on 3D Finite Element Methods. Results indicate that viscoelastic analyses provide more discriminating assessment of damage phenomena along the depth of pavement layers, and that landing gear geometric characteristics are more diagnostic than aircraft gross weight for cumulative damage propagation.

Performance mix asphalt concrete wearing course with addition of plastic bottles of polyethylene terephthalate

The performance of the modified asphalt concrete pavement structure is done because of the increasing traffic load that occurs along with population growth. The study is needed to review the pavement structure whether it is still able to withstand the load or not at all. An Evaluation was carried out using Falling Weight Deflectometer (FWD) field data to obtain deflection data. Laboratory testing of UMATTA used modified asphalt mixture using Polyethylene Terephthalate (PET) type plastic bottle waste to obtain the relative strength coefficient value as an application combined with secondary data from average daily traffic data on the roads of the Batas Medan City– Batas Lubuk Pakam City. Structural analysis shows that the entire segment requires an added layer with the thickness that is different due to the segmentation performed. In this study to maintain the required service level, namely SCI>1, the pavement must receive periodic maintenance and routine maintenance. elated to using asphalt modification using PET will produce a lower pavement thickness of 11 cm compared to the pavement thickness by the 2017 Pavement Design Manual standard of 16 cm.

Structural Response Analysis of Nonlinear Pavement Based on Granular Material

For containing gravel layer structure of flexible asphalt concrete pavement structure, the response laws of gravel pavement structure under elastic and nonlinear were comparatively analyzed through the UMAT subroutine programming and FEM. The results show that when considering the nonlinearity of gravel base, the tensile stress and vertical stress of base layer in pavement structure are quite different from linearity condition. With the increase of the load, the tensile stress of the base layer increases nonlinearly, and is less than that of the elastic gravel material under heavy load. Considering the non-linear condition of gravel, the vertical stress of pavement structure increases and mainly occurs in the gravel base.

Performance evaluation and field application of hard asphalt concrete under heavy traffic conditions

In order to improve the service performance of asphalt pavement under high temperature and rain during summer under heavy traffic conditions, this research compared the pavement performance of hard, heavy-duty AH-70, and Styrene Butadiene Styrene (SBS) polymer-modified asphalt mixtures through high temperature performance, low temperature crack resistance, fatigue resistance, and water stability tests. Results indicate that 30# hard asphalt mixture remarkably improves high temperature performance compared with 70# and 70# SBS asphalt mixtures. Moreover, the water stability of these asphalt mixtures is comparable. The fatigue performance of 30# hard asphalt mixture is comparable with that of 70# asphalt mixture. Finally, after 10 years of pavement performance, the hard asphalt concrete pavement structure achieved the best road conditions.

Selection of a performance test to assess the cracking resistance of asphalt concrete materials

Cracking is a common failure mechanism in asphalt concrete pavement structures. It is one of the main reasons for large road maintenance and rehabilitation expenditures, as well as reduced user comfort and increased fuel consumption due to high road roughness. The resistance of the pavement to this distress mechanism is dependent upon the ductility of the asphalt pavement mixture. The use of recycled asphalt materials in asphalt mixtures are also becoming increasingly common. A drawback of this practice is a reduction in ductility of the asphalt mixture, which causes a significant reduction in the fatigue life of the pavement in many cases. In Oregon, asphalt pavements are commonly failing prematurely due to cracking-related distresses, necessitating costly rehabilitation and maintenance at intervals of less than half of the intended design lives in some cases. For this reason, it is necessary to accurately quantify the impact of increasing the recycled asphalt content in asphalt pavement on the structural cracking resistance of the pavement through the use of low-cost and efficient testing procedures that can be implemented easily. This study focuses on characterizing the cracking performance of asphalt pavements in Oregon by considering four tests commonly used to evaluate fatigue cracking resistance and proposing the implementation of the most cost-effective and efficient test procedure for agencies and contractors.

Study on the Test System of Yunluo Long-life Asphalt Experimental Road

In order to grasp the mechanical response of the asphalt concrete pavement structure, on the basis of the layer theory of the asphalt pavement structure and the measurement system, the measured data post-processing application of the asphalt pavement structure was developed. Based on the Yunluo expressway experimental section of Guangdong Province, according to the calculation theory of road structure, the finite element analysis model of the pavement structure was established, and the mechanical properties of the asphalt pavement structure of the experimental section were analysed. It was determined that the layout scheme of the asphalt pavement corresponding structure layer temperature and strain sensor and the road test plan based on FWD. By using FWD as the loading tool, the resistance strain sensor were used to dynamically monitor the transverse and longitudinal strains of the road structural layers in order to grasp the dynamic response of the asphalt pavement. By using the FWD's own deflection detection system, the measured deflection data of the pavement structure were obtained. At the same time, taking into account the processing difficulties of mass measurement data, the postprocessing application of the measured data was developed. The results show that according to the theoretical analysis, the measured system was reasonable, the layout scheme and the test plan were proper. The measured data postprocessing applications can offer a better analysis platform for analysts.

Diagnostic Testing on Crack Propagation of Asphalt Pavement Materials

Asphalt concrete is a typical road building material of advanced asphalt pavements. Under the reciprocating vehicle loading, fatigue cracks are reduced inevitably, which seriously affect road performance. Therefore, effective detection and diagnosis of fatigue crack propagation has become a hot research issue. Acoustic emission detection test is a new dynamic nondestructive testing technology which has some features of real-time, online and overall detection. The main purpose of this paper systematically analyses the development process of acoustic emission technology applied in health monitoring field of asphalt concrete pavement structure, and to state the acoustic emission source localization principle, the parameters of acoustic emission signal analysis method, the acoustic emission signal waveform analysis method, etc. Furthermore, from the aspects of the asphalt concrete fatigue performance, crack evolution process and positioning technology, this paper fundamentally discuss the future technological development prospect of acoustic emission technology which is applied in the field of monitoring and diagnosis of asphalt concrete pavement structure, and provide a new perspective for the whole dynamic maintenance of road , and the information implementation of pavement maintenance strategies at later stage.

Three-dimensional modelling of multilayered asphalt concrete pavement structures: strain responses and permanent deformation

In any given asphalt concrete (AC) pavement structure, the permanent deformation (PD) in each AC layer has an influence and contributes differently to the total pavement rutting. The degree of influence will generally vary as a function of the AC modulus and layer thickness. Presently, most of the AC material/layer PD characterisation and analyses are based on laboratory and/or field testing in combination with stress-strain modelling under assumed circular and uniformly distributed wheel loading. In this paper, a three-dimensional finite element program, ANSYS, incorporating measured vertical tyre–pavement contact pressure (TPCP) was utilised for computing the PD of each AC layer with different variables such as the AC layer modulus, AC layer thickness, TPCP levels, vertical wheel loads, and tyre inflation pressure. A strain energy concept was also proposed for evaluating the PD rate and contribution of each AC layer. The corresponding results indicated the following: (1) the PD contribution of each AC layer varies as a function of the AC modulus as theoretically expected; (2) the intermediate AC layer significantly contributes to lateral deformation; however, both the intermediate and top AC layers significantly contribute to vertical PD; (3) the AC layer thickness and the magnitude of the lateral TPCP hardly influence the PD of the intermediate AC layer; (4) the PD influence of small light trucks can be quite substantial depending on the loading conditions and cannot be neglected in the analysis of this nature; (5) the distribution of the TPCP has a very significant influence on the PD of the top AC layer and is more pronounced as the TPCP gets more non-uniformly distributed.

Effect of confinement pressure on the nonlinear-viscoelastic response of asphalt concrete at high temperatures

Asphalt concrete materials exhibit nonlinear viscoelastic responses at high stress/strain levels. The traffic loading induces multi-axial stress states within the asphalt concrete pavement structure. Therefore, it is imperative to characterize the nonlinear viscoelastic responses of asphalt concrete under the realistic multi-axial stress states. Available methods in the literature for characterizing the viscoelastic nonlinearity are mostly based on simple uniaxial creep-recovery tests without considering the effect of confinement stress levels.In this paper, the nonlinear viscoelastic properties of asphalt concrete materials are characterized considering the effects of confinement pressure. It is shown that the confinement pressure significantly affects the nonlinear viscoelastic response of asphalt concrete materials. The viscoelastic nonlinearity is characterized as a function of triaxiality ratio in order to capture the combined effects of confinement level and deviatoric stress. Cyclic creep-recovery tests are performed at 55°C and at different confinement levels. An equation is proposed to relate the nonlinear viscoelastic parameters to the triaxiality ratio based on the test results. The analyses showed that the triaxiality ratio has substantial effect on the nonlinear strain response of the asphalt concrete.

Elastoplastic Analysis of Asphalt Concrete Pavement

Drucker-Prager linear elastic-perfectly plastic model and the associated flow rule, a numerical simulation study has been conducted on the layered asphalt concrete pavement structure, using the 2D axisymmetric finite element method (FEM). Pursuant to empirical equation of the stability, cohesion and internal friction angle of asphalt concrete, and in line with experimental test subjects on pavement material and pavement performance, the impact of mechanical parameters of each layer of asphalt concrete on the road surface deflection and the evolution law of plasticity in each structural layer under standard axle load has been studied.

Effects of Layer Interfacial Bonding Conditions on the Mechanistic Responses in Asphalt Pavements

The bonding condition between pavement layers plays an important role in the performance of pavement structures. In this paper, a three dimensional finite-element (3D-FE) program was used for modeling the mechanistic responses (stresses and strains) in the asphalt concrete (AC) layers by simulating two layer interfacial bonding conditions, namely fully bonded and debonded (i.e., the layer separated but still considering friction). The 3D-FE modeling incorporated actual measured vertical tire-pavement contact pressure (TPCP) and assumed horizontal TPCP, including investigating the effects of vehicle acceleration and deceleration. The results of these computational modeling are presented in this paper and indicated that the layer interfacial bonding condition has a significant effect on some pavement mechanistic responses such as the tensile, compressive, and shear stresses/strains in AC pavement structures. In general, layer interface debonding (or separation) was analytically found to indirectly exacerbate pavement distresses such as slippage cracking, fatigue cracking, shoving, shear deformation, and rutting, which is undesirable.

Mechanistic-Empirical Study of Effects of Truck Tire Pressure on Pavement: Measured Tire-Pavement Contact Stress Data

Truck tire pressure plays an important role in the tire-pavement interaction process. As a traditional approximation method in many pavement studies, tire-pavement contact stress is frequently assumed to be uniformly distributed over a circular contact area and simply equal to the tire pressure. However, recent studies have demonstrated that the tire-pavement contact stress is far from uniformly distributed. In this study, measured tire-pavement contact stress data were input to a finite element program to compute pavement immediate responses for three tire configurations: single tires, dual tires, and dual-tire tandem axles. Computed critical pavement responses were input to pavement distress transfer functions to analyze further the effects of tire inflation pressure on pavement performance. Two asphalt concrete pavement structures— a thick pavement and a thin pavement—were investigated. Pavement responses at selected locations in the pavement structures were computed by the finite element program using...

Mechanistic–Empirical Study of Effects of Truck Tire Pressure on Pavement

Truck tire pressure plays an important role in the tire–pavement interaction process. As a traditional approximation method in many pavement studies, tire–pavement contact stress is frequently assumed to be uniformly distributed over a circular contact area and simply equal to the tire pressure. However, recent studies have demonstrated that the tire–pavement contact stress is far from uniformly distributed. In this study, measured tire–pavement contact stress data were input to a finite element program to compute pavement immediate responses for three tire configurations: single tires, dual tires, and dual-tire tandem axles. Computed critical pavement responses were input to pavement distress transfer functions to analyze further the effects of tire inflation pressure on pavement performance. Two asphalt concrete pavement structures–-a thick pavement and a thin pavement–-were investigated. Pavement responses at selected locations in the pavement structures were computed by the finite element program using the measured tire–pavement contact stress data and compared with the results predicted by a multilayer program using the traditional uniform contact stress method. The computation results showed that the multilayer program and the traditional tire model tend to overestimate the horizontal tensile strains at the bottom of the asphalt concrete and underestimate the vertical compressive strains at the top of the subgrade. Prediction of effects of tire pressure on pavement performance shows that increased tire pressure results in increased pavement distress due to both cracking and rutting and that tire inflation pressure is also related to the shape of pavement ruts.

Analytical Study of Effects of Truck Tire Pressure on Pavements with Measured Tire–Pavement Contact Stress Data

Truck tire inflation pressure plays an important role in the tire–pavement interaction process. As a conventional approximation method in many pavement studies, tire–pavement contact stress is frequently assumed to be uniformly distributed over a circular contact area and to be simply equal to the tire pressure. However, recent studies have demonstrated that the tire–pavement contact stress is far from uniformly distributed. Measured tire–pavement contact stress data were input into an elastic multilayer pavement analysis program to compute pavement immediate responses. Two asphalt concrete pavement structures, a thick pavement and a thin pavement, were investigated. Major pavement responses at locations in the pavement structures were computed with the measured tire–pavement contact stress data and were compared with the conventional method. The computation results showed that the conventional method tends to underestimate pavement responses at low tire pressures and to overestimate pavement responses at high tire pressures. A two-way analysis of variance model was used to compare the pavement responses to identify the effects of truck tire pressure on immediate pavement responses. Statistical analysis found that tire pressure was significantly related to tensile strains at the bottom of the asphalt concrete layer and stresses near the pavement surface for both the thick and thin pavement structures. However, tire pressure effects on vertical strain at the top of the subgrade were minor, especially in the thick pavement.

Analytical Study of Effects of Truck Tire Pressure on Pavements with Measured Tire-Pavement Contact Stress Data

Truck tire inflation pressure plays an important role in the tire-pavement interaction process. As a conventional approximation method in many pavement studies, tire-pavement contact stress is frequently assumed to be uniformly distributed over a circular contact area and to be simply equal to the tire pressure. However, recent studies have demonstrated that the tire-pavement contact stress is far from uniformly distributed. Measured tire-pavement contact stress data were input into an elastic multilayer pavement analysis program to compute pavement immediate responses. Two asphalt concrete pavement structures, a thick pavement and a thin pavement, were investigated. Major pavement responses at locations in the pavement structures were computed with the measured tire-pavement contact stress data and were compared with the conventional method. The computation results showed that the conventional method tends to underestimate pavement responses at low tire pressures and to overestimate pavement responses at...

Evaluation of Permeability of Superpav® Asphalt Mixtures

The presence of water in a pavement system is detrimental to its life. Permeable asphalt concrete pavement structures are vulnerable to stripping, which causes premature damage under heavy traffic. To assess the permeability of asphalt mixtures, a research study was conducted at the Louisiana Transportation Research Center (LTRC). Laboratory permeability tests were performed on field cores taken from 17 Superpave® projects in Louisiana. An LTRC-modified version of Karol-Warner's falling-head permeameter was used to conduct the permeability test. A sensitivity analysis was performed to relate the permeability test results to mixture volumetric properties such as air void content, compaction effort, mixture gradation, and lift thickness. A statistical regression model was developed to predict the permeability of Superpave mixtures from the mixture volumetric properties. The model successfully predicted the coefficient of permeability of asphalt mixtures from a separate data set that was not included in the model development.