Experimental Analysis of Interface Shear Fatigue Performance of Ultra-Thin Whitetopping

摘要

The good quality of the bond between the substrate and the overlay is a key factor for providing composite or monolithic action in Ultra-Thin Whitetopping (UTW) by shifting the neutral axis from middle of the UTW slab to the bottom of UTW slab. This will reduce the bending stresses, however, shear stress will remain maximum at the interface. The shear stress at the interface will increase with the increase in repeated application of traffic load which creates an accumulation of strain at the interface resulting in failure of the monolithic action and finally affects the long-term performance of UTW. In this study, a strategic test apparatus and procedure are used to evaluate the decrease in bond strength caused by cyclic loading with respect to different interface treatment. The direct shear test was performed at 7 , and 28 days and parameters like interface bond strength, tangential stiffness (k-modulus) and a number of cycles at failure for different stress ratios were collected through the experiments of different interface conditions. Through comparison of test results of different interface treatment with different loading rate and interface shear fatigue, it proved that this test method and the device can evaluate interface bond strength of UTW under static and repeated loading conditions effectively.