Dynamic Response of Asphalt Pavement on Semi-Rigid Base due to Heavy Load

2013 ◽  
Vol 405-408 ◽  
pp. 1745-1752
Author(s):  
Li Juan Zhang

The purpose of this paper is to study dynamic-characteristics of asphalt-pavement on semi-rigid base loaded with moving, heavy-load. Based on transient-dynamics theory, three-dimensional finite-element (FE) model was developed for structural dynamic-responses analysis using ANSYS software. The heavy-duty axle-load model was established according to Belgium-Design Code, and the dynamic-load was simplified as sinusoidal-wave load. For the pavement mechanics indexes (road-surface deflection, the vertical and lateral stress, the shear stress and the strain), the time-history curves and distribution conditions in the structure were presented. Expect tensile-strain at surface-layer, the relationship between axle-load weight and mechanic-indexes are almost linearly proportional. The calculation shows that under moving heavy-load, the surface-layer suffers from rather high vertical compressive-stress and shear-stress, the base and subbase are loaded with high tensile-stress and the subgrade top undergoes large vertical-strain . For asphalt-pavement on semi-rigid loaded with moving, heavy-load, besides the conventional indexes (including road-surface deflection and tensile-stress at the bottom of base or subbase), the design indexes should also include the shear-stress on road surface, the vertical-strain on the top of subgrade and the vertical compressive-stress on road surface.

2011 ◽  
Vol 368-373 ◽  
pp. 193-196
Author(s):  
Xiao Hua Wang ◽  
Ji Shu Sun ◽  
Tian Xiao ◽  
Hui Ran Pi

Asphalt layer modulus is one of the important mechanical parameters in pavement design. It will directly influence the design result and the mechanical properties of asphalt pavement structure. Using pavement design and analysis software, the effects of asphalt layer modulus on surface deflection, tensile stress at the bottom of base and sub-base course, stress at the the bottom of asphalt layer and service life of heavy load semi-rigid asphalt pavement structure were analyzed systematically. And the influencing laws were analyzed, too. The results indicate that the mechanical properties, deforming characteristics and service life of heavy load asphalt pavement were influnced significantly by asphalt layer modulus. With the increasing of asphalt layer modulus, the surface deflection, tensile stress at the bottom of base and sub-base course would significantly decrease, and service life of heavy load semi-rigid asphalt pavement structure would be improved.


2012 ◽  
Vol 450-451 ◽  
pp. 267-272 ◽  
Author(s):  
Peng Wang ◽  
Can Cui

In recent years the research on Surface-initiated longitudinal cracking along wheelpath (or Top-Down cracking) is become a fresh hotspot in the field of pavement damage focused by international asphalt pavement engineering.Because the traditional load is the vertical surface load with uniform tire pressure, this loading is applied at only one position and no effort is made to distinguish between tire pattern.The traditional method can’t explain the mechanism of the top-down cracking. In order to discuss the mechanism of TDC, this paper establish a 3D finite element model of semi-rigid pavement structure and use the large finite element software Abaqus. The analysis shows that, in the crack beginning stage, the main tensile stress appears under the center of the load on the sub-base of the pavement,and its value increases with the time. When cracks appear in the base, the position of the main tensile stress appears at the bottom of the surface layer, under the outside edge of wheel path. The value of the main shear stress increases at the stage of the cracks beginning, but the increase is small. The value of the main shear stress decreases when the cracks appear in the middle of the surface layer, and the position of the main shear stress changes with the depth of the cracks. With the increase of the cracks’ depth, the adverse influence of the shear stress becomes weaker and weaker.So the key of controlling the cracks in the surface layer is prevention. To prevent the development of the cracks, the tensile strength of the layer’s material should be enhanced in any way. The stress and its value resulted from the vehicle loaded on the structure layer is bigger than the other cases when the position of the cracks is at the edge of wheel path, and the stress is much bigger than the shear strength and the fracture toughness of the material of the layer. As the shear strength of the material is not enough, the vertical cracks are easier to appear at the edge of wheel path under the load of the vertical. Once it appearing, the cracks will extended into the layer because of the load of vertical. Eccentric load generates greater stress in the structure than the load loaded upright. In fact, though, non-channeling can reduce the appearance of the tracks, eccentric load enhance the development of the cracks in the surface because of the existence of the cracks in the surface layer.


2012 ◽  
Vol 594-597 ◽  
pp. 1377-1381 ◽  
Author(s):  
Hong Lu Mao ◽  
Pei Zhi Zhuang ◽  
Ya Nan Zang ◽  
Xiao Ming Yi

To solve the early destruction problems occurred when overlaying asphalt pavement structure containing semi-rigid base on broken cement concrete pavement, finite element software is used to compare the stress characters between the repaving pavement and ordinary pavement, and analyze the repaving structures under different loads and different road transverse grade. It shows that the value of compressive stress at the top of base of repaving pavement is significantly higher than that of ordinary pavement, meanwhile, its value of tensile stress of base bottom is lower; the asphalt surface and new base top of repaving pavement need to bare a high value of shear stress and compressive stress under overload, so it’s prone to splitting failure in the base. With the increase of transverse grade, both the shear stress difference of road surface and maximum vertical compressive at top of the base increase in a lower position, but the situation is opposite in the higher position.


2013 ◽  
Vol 645 ◽  
pp. 471-475
Author(s):  
Jian Jiao ◽  
Shu Dong Meng ◽  
Qiang Jiao ◽  
Nan Li

In order to research the mechanical response of asphalt pavement under horizontal load which produced by the large aircraft braking process, large-scale finite element software is used in this paper. The model of main landing gear load is established to analyze the change of principal mechanics indexes of airfield pavement when the aircraft has different landing distance. The results show that: the horizontal load has a significant influence on the normal stress of landing direction, but the influence area is concentrated in the rear of the wheel. The horizontal load has more effect on horizontal shear stress and longitudinal shear stress, while has less effect on tensile stress of surface layer bottom, tensile tress of base course bottom and transverse shear stress. The tensile stress of surface layer will increase significantly when the braking distance is less than 2000m. Meanwhile, thickening surface layer could decrease the tensile stress and increase the fatigue lifetime apparently.


2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Chen Zhang ◽  
Yong Lei

To improve the durability of asphalt pavement with heavy traffic conditions in cold regions, the parameter optimization of graded macadam transitional layer (GMTL) for the inverted asphalt pavement based on the mechanical response and the strength standard was studied. The stress distribution laws of GMTL were studied with different loads by means of BISAR3.0. The influences of the thickness and the modulus of GMTL on the pavement stress were analyzed. The optimal thickness and the modulus range of the GMTL were determined. Combined with a self-developing real-time data acquisition and a processing system for aggregate attitude (RDAPS), the strength control standard of the GMTL was established. Finally, the performance of the optimized inverted asphalt pavement structure was verified through the MEPDG design method. The results show that the tensile stress at the bottom of the surface layer reduced by about 58%, and the shear stress in GMTL increased by about 17% when the modulus of GMTL increases from 300 MPa to 800 MPa. However, the change in modulus has no significant influence on the maximum shear stress in the asphalt surface layer and the tensile stress in the base layer bottom. When the thickness of GMTL increases from 12 cm to 20 cm, the tensile stress in the bottom of the base layer reduced by about 31%. Based on the mechanical results from simulation calculation and the technical indicator required in the field, the recommended optimal parameters of GMTL are the modulus of 700 MPa and the thickness of 18 cm. In addition, the spatial attitude angle ΦN of wireless intelligent attitude aggregate (WIAA), the compressive strength Rc standard, and the California Bearing Ratio (CBR) standard were analyzed, and the strength control standard of inverted asphalt pavement with GMTL was proposed, namely, CBR ≥ 354%, Rc ≥ 1.06 MPa, and ΦN ≤ 3°. A significant improvement in the resistance to crack can be seen in the inverted asphalt pavement when the optimized structure was applied. Taking the 20-year service life as an example, the top-down cracks reduced by 29.3% and the bottom-up cracks reduced by 32.6% in comparison to the original structure. The recommended structural parameters of GMTL could be used to guide the construction and design of inverted asphalt pavement in cold regions.


2011 ◽  
Vol 97-98 ◽  
pp. 28-31 ◽  
Author(s):  
Tian Xiao ◽  
Hui Ran Pi ◽  
Can Zhang Jin

Subgrade resilience modulus is an important mechanical parameter in pavement design. It will directly influence the design result of pavement structure. Using BISAR3 of SHELL design method, the impacts of subgrade resilience modulus on pavement surface deflection, base and subbase bottom tensile stress, surface layer bottom tensile stress of the heavy load asphalt pavement structure were analyzed. And the influencing laws were analyzed, too. The results show that the mechanical and deforming characteristics of heavy load asphalt pavement were influnced significantly by subgrade resilience modulus. With the increasing of subgrade resilience modulus, the pavement surface deflection, base bottom tensile stress would significantly decrease, and fatigue life would be improved.


2013 ◽  
Vol 723 ◽  
pp. 22-26 ◽  
Author(s):  
Pei Long Li ◽  
Zhan Ding ◽  
Zheng Qi Zhang

Aging is a main factor affecting the durability of asphalt pavement. To study decay behavior of asphalt pavement with aging, aged asphalt was extracted from stratified pavement mixtures for different service-life. The changes of asphalt properties with service time and depth variations of the pavement were discussed. And numerical simulation analysis of pavement structure was conducted with pavement gradient modulus changes caused by aging. The results indicate that asphalt stiffness increases and low-temperature performance decays sharply with the extension of pavement service life, especially in the first several years. The vertical aging differences from top to bottom of pavement were significant, the aging extents decrease continuously from the surface, which cause the gradient changes of pavement modulus. The maximum tensile stress and maximum shear stress all increase with surface modulus increasing, so more serious aging can induce greater gradient modulus, shear stress and tensile stress are larger under the same loads, which have more serious damage to the pavement structure.


2014 ◽  
Vol 580-583 ◽  
pp. 632-635
Author(s):  
Li Ya Su

With the rapid development of traffic cause in our country, the operating requirement of driving load factors to pavement structure become higher and higher. The Semi-rigid base asphalt pavement structure exposed some defects and shortcomings, so the study of flexible base asphalt pavement structure is put on the agenda under the circumstances.Based on the research achievements at home and abroad of the existing asphalt pavement structure , choosing different elastic modulus and thickness to calculate and analyze the flexible base by ANSYS, gaining the law and trend of mechanics response (the vertical displacement and tensile stress) about pavement structure for the flexible base pavement of each layer foundation to provide the design reference.


2012 ◽  
Vol 178-181 ◽  
pp. 1183-1187
Author(s):  
Er Yong Chuo ◽  
De Qun Wang ◽  
Guo Rui Deng

At the beginning,we used the ABAQUS to establish a two-dimensional finite element model of typical asphalt pavement, and analysised the changing axiom of road surface shearing stress under the half sine wave load. Also, we studied on the impact of damping ratio and the driving speed on shearing stress. Finally, by using SPSS13.0 software to compare the impact of speed, the surface layer material damping ratio, lower modulus ratio, the thickness of the surface layer and the thickness of the subbase. The results show that, to reduce the cracking damage caused by oversized shearing stress in asphalt pavement, we should first consider the damping ratio of surface layer material, and the most effective method is to use the road-building material of high damping ratio to prevent cracks, at the same time we should raise the driving speed.


2013 ◽  
Vol 361-363 ◽  
pp. 1869-1872 ◽  
Author(s):  
Sheng Jie Liu ◽  
Qing Long You

This paper examines theoretically the possible mechanical response changes on both bituminous pavement structure using linear elastic method, the change regulation of deflection,stress on the bottom of base and subbase and compress strain on the top of subgrades between semi-rigid base and flexible pavement pavement. In the load application procedure, a dual wheel with the a series of pressure was chosen.The results have shown that the deflection tensile stress and subgrade compressive strain on the surface increase with the increase of axle load and they would result in serious effect of overloading on the earlier damage of asphalt pavement.


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