Effect of aggregate size on the dynamic interfacial bond behaviour between basalt fiber reinforced polymer sheets and concrete

This experimental investigation examines the influence of coarse aggregate size (i.e. 5-10 mm, 10-15 mm, and 15-20 mm) on the dynamic interfacial bond behaviour between BFRP and concrete under various loading speeds (i.e. 8.33E-6, 0.1, 1.0, 3.0, 5.0, and 8.0 m/s). The testing results including the interfacial bond strength and bond-slip responses are evaluated and discussed. For the specimens with the same coarse aggregate size under different loading speeds, the ultimate debonding strain of the BFRP sheets subjected to dynamic loading is higher than that under static loading, and the debonding load and peak shear stress increase with the rising loading speed. For the specimens with different coarse aggregate sizes under the same loading speed, the peak interfacial shear stress slightly reduces with the rising coarse aggregate size. However, the variation of the interfacial shear stress is marginal when the loading speed is over 3 m/s due to the debonding surface shifted from concrete substrate to the concrete-epoxy interface. The proposed bond-slip model by incorporating the effects of coarse aggregate size and strain rate matches well with the testing results. (C) 2019 Elsevier Ltd. All rights reserved.