Study on anti-crack effect of semi-rigid base pavement with stress absorbing layer

Abstract

For the characteristics of semi-rigid base asphalt pavement prone to cracking, various stress-absorption layers are applied widely by decreasing stress concentration, improving interlayer bonding and waterproofing. Existing studies on the anti-cracking effect of stress absorbing layers rarely consider top-down fatigue cracking on the outside of the boundary of the vehicle loading zone. Firstly, this paper proposes a finite element model setting a downward expansion of fatigue crack in pavement based on fracture mechanics. The influence law of modulus and thickness of stress absorbing layer on stress intensity factor of crack tip and the fatigue life of the pavement is analyzed furthermore. Numerical calculation results demonstrate that shearing stress intensity factor increases with stress absorbing layer thickness and decreases with stress absorbing layer modulus, while fatigue life of pavement grows with the modulus of the stress absorbing layer and decreases with its thickness. Sensitivity analysis indicates that the modulus of the stress absorbing layer has a greater effect on the fatigue life of the pavement relative to thickness, which offers reference for further promotion and application of stress absorbing layer.