Interface shear behaviours between recycled concrete aggregate and geogrids for pavement applications

The usage of recycled concrete aggregate (RCA) in pavement applications is a sustainable approach for future infrastructure development, given the significant environmental benefits. Geogrid reinforcement of RCA can also improve the tensile and flexural strengths of the pavement structure to sustain high traffic loadings. The effect of aperture size, tensile strength of geogrids, normal stress and gradation on shear interaction between geogrids and RCA was investigated in this research, with the usage of a large-scale direct shear test (LDST) apparatus. Three types of biaxial geogrids, with different aperture sizes and tensile strengths, and two RCA samples with different gradations were used in this study. The interface shear strength was found to be highly dependent upon the aperture width of the geogrids, D, as well as the RCA particles finer than the aperture width of geogrid, F-D. Based on the analysis of test results, a linear relationship between interface shear strength coefficient, alpha, the ratio of interface shear strength of geogrid/RCA and shear strength of RCA was proposed, with respect to the D/F-D ratio. The proposed relationship will be useful for a rapid assessment of the interface shear strength coefficient of geogrid-reinforced RCA based on the aperture size of geogrids and RCA gradation properties.