Evaluation Methods Of Tack Coat And Stress Absorbing Interlayer

Shear slip and reflect crack are two of the most serious damages in asphalt pavement. As there are several different kinds of methods in shearing and cracking test, The research aimed at building an unified test methods and evaluating index. a multi-function interlayer stress tester, which could be used on both shearing and cracking testing.Firstly, mechanism of shear slip was studied, bonding and friction were thought to be the key factors to improve shear resistance, the pull-apart function could be used on bonding strength measurement only, shear-apart function could be used on the combine effection fo both bonding and friction. Some common pavement structure were tested by the two method, the reason and evaluation were analized either. Tests appeared that interface with SBS modified emulsion showed better shear strength than SBR modified emulsion.Then, mechanism of reflecting crack was studied either. Stiffness of stress absorbtion interlayer was thought to be the key factors, three kinds of stress absorbtion interlayer were tested by the instrument, including SAMI, SAMPAVE and STRATA, the stiffness modulus and anti-crack funtion were evaluated by the curves of stress-strain.Tests appeared that STRATA and SAMPAVE showed much better performance on anti-crack than SAMI.