Abstract
The horizontal strain at the bottom of asphalt concrete is well accepted as a key influencing factor in pavement performance and is directly related to fatigue cracking. This article presents the results of several studies performed in the field that focused on the evaluation of the effect of the base on the pavement dynamic responses under moving vehicular load through embedded strain gauges. Strain gauges were embedded at the bottom of the asphalt and base layers to measure pavement responses under moving vehicular loading. The investigated types of bases include a semirigid base, inverted base, compound base, and roller compacted concrete (RCC) base asphalt pavements. The effect of axle load level, tire pressure, and vehicle speed on pavement responses were analyzed based on the measured strain. Results showed that the critical horizontal strain at the bottom of the asphalt layer increased as the axle load increased, whereas the influence of the vehicle speed conversely affected the critical horizontal strain. The combined effect of the high temperature on the road surface and overload of the vehicle significantly increased the strain response at the bottom of the asphalt layer. Moreover, it was found that because of the modulus dependency of the pavement base, the horizontal strain at the bottom of both asphalt and base layers for RCC base pavement was smaller than that of the other three base types.
