Interlaminar interface shear slip characteristics of composite pavement

Based on the composite pavement test section of Nandaliang Expressway, the exposed bone ratios and texture depths of different roughened interfaces were tested, and 45°shear tests were carried out with core samples drilling in the field test section. Combined with 45°shear test results and the mechanical properties in the interlaminar shear process, the interlaminar shear and deformation curve was divided into four stages: elastic stage, failure stage, shear strength reduction phase, and residual phase. The interlaminar shear and deformation behavior was evaluated by using the texture depth, peak shear strength, relative interlaminar slip displacement corresponding to the peak shear strength, and residual shear strength. The effects of interface roughness mode, types and amounts of waterproof cohesive materials, temperature, and loading rates on the interlaminar shear and deformation characteristics of composite pavement wereanalyzed. Test result shows that the texture depth of the chiseling interface (1.17 mm) is greater than that of the sand-blasting interface (0.37 mm). Combined with the interlaminar mechanical property differences of different roughened interfaces in the shearing process, the composite specimen formed at the chiseling interface has better shear resistance performance than that formed at the sand-blasting interface. The relative interlaminar sliding displacement corresponding to the peak shear strength of the chiseling interface (0.19-0.79 mm) is larger than that of the sandblasting interface (0.16-0.33 mm) with the same waterproof cohesive materials. Moreover, the effect of waterproof cohesive materials on the peak shear strength and residual shear strength is greater than that of the interlaminar relative slip displacement corresponding to the peak shear strength. As a whole, the effect of temperature on interlaminar shear and deformation characteristics is remarkable, and the peak shear strength at 5℃is 7.0-10.0 times of the value at40℃. The test conditions have a great influence on the interlaminar shear strength, and the interlaminar peak shear strength measured at 50 mm·min^-1 loading rate is 1.9-3.5 times of the value measured at 5 mm·min^-1 loading rate. Thus, the chiseling roughened method is more helpful to improve the interlaminar shear strength of the composite pavement, and the multiindex should be used to evaluate the interlaminar shear and deformation characteristics of the composite pavement.