Proof and Control of Structural Modulus Gradient for Pure Flexible Pavement

Abstract

Flexible base asphalt pavement was gradually applied in high-grade highway recently. Whether pavement is designed properly directly affects operating life and durability. Proper modulus gradient-controlling of structural layers was useful for structure stress. In order to further verify the necessity of modulus gradient-controlling of structural layers, the paper chose modulus ratio between base and surface affecting stress distribution of structure most obviously as entrance point, set interlayer binding condition as not fully continuous and then comprehensively calculated the mechanical responses of flexible pavement with modulus ratio between base and surface changing by shell designing software Bisar3.0, so the effect of modulus ratio was quantified. The results showed that when modulus ratio between base and surface changed from 8 to 14, maximum flexible strain of asphalt layer and maximum flexible stress of structure both showed the trend of increasing, at the same time shear stress of surface decreased; Controlling flexible stress and shear stress together and taking higher value of base module in proper scale was good for structure to keep mechanical balancing. It was suggested to control modulus gradient-controlling of structural layers at the scale from 8 to 10.