Cracking of the PCC layer in composite pavement.

Abstract

An asphalt concrete (AC) overlay of a jointed plain concrete pavement (JPCP) is intended to extend the service life of the existing pavement structure. Also known as composite pavements, such pavements exhibit features of both rigid and flexible pavements. While behavior of rigid pavements is mainly elastic, behavior of asphalt layer is load-duration dependent. At the same time, temperature curling causes non-linear interaction with the foundation. The available models of composite pavement ignore the behavior of the load duration dependent asphalt layer when the composite pavement is subjected to a combination of temperature curling and traffic loads. This research concentrates on the improvement of structural modeling of composite pavements subjected to slow developing temperature curling and instantaneous traffic loads. A finite element (FE)-based model accounting for the viscoelastic behavior of the asphalt layer in composite pavements is developed and verified using comparisons with semi-analytical solutions obtained in this study. In order to maintain compatibility with the Mechanistic-Empirical Pavement Design Guide (MEPDG) framework, a simplified procedure is developed. The procedure uses a different asphalt modulus for curling than for axle loading and determines the total stresses in the pavement as a combination of the stresses from solutions of three elastic boundary value problems. The simplified procedure is compared with the existing MEPDG model for fatigue cracking in AC overlaid JPCP. A framework for the implementation of the proposed model into the MEPDG is also developed.