Shearing Behaviors Of Asphalt Overlay Upon Concrete Pavement And Its Applications

Asphalt concrete pavement (cement concrete pavement to asphalt surface), because it can effectively improve the performance of old cement road and make full use of the old cement road surface, also be of low cost, easy construction, low effect on road traffic and the environment, it is the dominant in the old cement road surface reconstruction project. But with the sharp increase of traffic and vehicle load, asphalt pavement translation over cement concrete pavement, humps on asphalt concrete pavement and other road diseases can be seen anywhere, especially on the roads in mountain. In current guide regulations, it only gives some instructions on road materials, construction method, and layer thickness for structure design of overlaying composite asphalt pavement on old cement concrete pavement. Especially, a big range is recommended for layer thickness control, the shear strength between layers is not taken into consideration. Thus a hidden danger is planted for early damage of pavement, which will have greatly effects on the durability of road.This research focus on the mechanical behaviors of asphalt overlay upon concrete pavement, especially the influencing factors on the shearing stress between layers and the shearing strength. The main works can be drawn as follows:â‘ Research on the distribution of shear stress in asphalt overlay upon concrete pavement.Calculation methods for shear stress in asphalt overlay upon concrete pavement were discussed, and derivation and Contrastive Analysis were performed. Based on Elastic Multi-layer System Theory, distribution and values of shear stress in asphalt overlay were analyzed. Correlation analysis were also carried out on influencing factors such as layer thickness, modulus of layers, bonding properties between cement concrete and asphalt overlay, friction coefficient, axle load and so on. Impact degree by each factors were clarified.â‘¡Research on the shear strength of asphalt overlay upon concrete pavement.By laboratory experiments indoors, the shearing strength of SMA-13, AC-16I and cement concrete were obtained, also the shearing strength between layers. Shear resistance envelope curves of asphalt overlay were achieved according to Mohr- Coulomb criteria.â‘¢Determining overlay thickness H considering the shear strength of asphalt overlay upon concrete pavement.A method for determination of the thickness of asphalt overlay H and the corresponding thickness of other layers were obtained by the calculated results of shear stresses and experimental data comparison.This study not only gives a reasonable explanation for early diseases of the old concrete pavement asphalt overlay, such as translation, humps, layer off and etc., but also its theoretical analysis and experimental data present a basis for further relative research. The method for determining asphalt overlay H also provides a reference for the road structure design. It has an great academic and practical value in road engineering.