Accelerated pavement testing and modeling of reflective cracking in pavements

Abstract : In the field of reflective cracking initiation and propagation in pavement structures, an Accelerated Pavement Testing (APT) has been developed. The numerical method is also supported. Numerical results obtained by calculations made with the finite element CESAR-LCPC software are then compared with the experimental data. The reflective cracking APT experience is the first step in the development of a new laboratory equipment to evaluate the design of bituminous layers to repair pavements. The experiment was performed on a 30 m track where eight discontinuities were established by cutting-off the sub-bases in order to ensure a crack development in the bituminous layer. The conditions that promote crack propagation were reproduced by the application of heavy periodic loads using the Fabac ALT-APT test rig. The width of the bituminous layer was decreased to facilitate the observation of the crack propagation, while avoiding creep of the material. The structure has a large number of sensors that measure longitudinal and transverse deformations at the bottom and at the surface of the bituminous layer. The deflections and the displacements are measured at several levels of the structure, as well as the temperature and the lateral edge cracking which is monitored by cracking sensors on both sides of the track. Preliminary results on two joints were used to determine the mechanisms of rupture of the structure. Four more tests with improved sensors have completed the information. Experimental and numerical results are compared in order to validate the analysis of the fatigue process (debonding, damage and cracking) in full scale pavement.