Analysis of Semi-Rigid Asphalt Pavement with Flexible Base as a Sandwich Layer

Reflective cracking is one of main distresses for cement/lime/flyash stabilized base in China. Although flexible base can be and has been utilized as sandwich layer to reduce reflecting cracks from stabilized base, the repetitive truck traffic load may cause higher tensile stress at the bottom of asphalt surface course because of large deformation from flexible base. The high tensile stress may lead to fatigue cracking. To minimize the tensile stress at the bottom of the asphalt layer and to establish optimum structures to reduce reflective cracking, nonlinear finite element technique was utilized to support three experimental pavements in Tonghua Highway in Jilin province. Base on the analyses, pavement structures 1 and 2 are recommended. In addition, for pavement structure 1, the optimal design is to include 7–12cm of AM-30, 10–15cm of flexible base, and 30–45cm of semi-rigid subbase (lime-flyash stabilized soil or cement treated base). Furthermore, for pavement structure 2, the optimal design is to include 15–20cm of flexible base, and 25–40cm of semi-rigid subbase (lime-flyash stabilized base or cement treated base).