Coupled Numerical Analysis of Anti-crack Mechanism of Large Stone Asphalt Mixture

Abstract

Stresses of pavement with flexible base of LSAM-30, ATPB-30 and A0-301 at the most adverse point under the function of traffic load and temperature load as well as the coupling of them were calculated and compared by finite element method. The result indicates that flexible bases of LSAM-30 and ATPB-30 are more effective in the prevention of reflection crack. Because of the great volume of coarse aggregate and large maximum nominal particle-size, the LSAM-30 thermal conductivity is greater, and the temperature shrinking coefficient is lower as well as the modulus of resilience, which could reduce the temperature gradient among the structure layers effectively and then diminish the thermal stress. At the same time, the adequate flexibility performance of the LSAM may also absorb strain energy at the crack of the semi-rigid subbase sufficiently. As a result, it presented preferable reflection crack resistance. A case study was conducted to do comparative analysis of anti-cracking performance of LSAM-30, ATPB-30 and AC-301 flexible bases. A long-term follow-up observation of test roads with the three bases shows that the pavement with LSMA base is in good condition and no sign of crack found while pavements with ATPB-30 and AC-301 flexible bases have varying degrees of crack. LSMA flexible base has an obvious performance of anti-crack.