Dynamic Response Of Asphalt Pavement Research Articles

Dynamic model and criteria indices of semi-rigid base asphalt pavement

This paper presents a dynamic model of asphalt pavement by considering the characteristics of moving tyre load, visco-elastic performance of material and layered system of pavement. The pavement is defined as an infinite layered system with the tyre load moving at a constant speed, and asphalt concrete (AC) is characterised as a kind of visco-elastic material. Using the spectrum analysis method, a complex tyre load is decomposed into a series of harmonic loads. Based on the frequency characteristics of a linear system, a universal formulation pattern for differential visco-elastic constitutive relations is provided. And then, a model is set up to analyse the dynamic response of asphalt pavement under moving harmonic load, and then to extend to the arbitrary moving load according to the superposition principle of a linear system. The dynamic responses of seven typical semi-rigid base asphalt pavements are analysed using the model. Analysis results indicate that the tensional strain at the bottom of the AC layer and the vertical compression strain at the top of the roadbed are not suitable for key indices of the semi-rigid base asphalt pavement. The shearing strain at the bottom of the AC layer can be taken as a key index to evaluate the fatigue performance, and the vertical compression strain at the top of the pavement surface can be taken as a key index to evaluate pavement rutting, and the vertical shearing strain at the top of pavement surface can be taken as a key index to evaluate top–down crack.

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

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.