Interfacial bonding performance of textile reinforced ECC and seawater sea-sand concrete under a dry-wet environment

Abstract

In order to promote the application of cementitious composites in the marine environment, it is crucial to clarify the interfacial bonding properties of cementitious composites to concrete. Therefore, the interfacial bonding performance of a new cementitious composite, textile reinforced ECC (TRE), to seawater sea-sand concrete (SWSSC) in a chloride salt dry-wet environment was investigated by single shear test. The interface behavior was evaluated from the failure modes, average bond strength, load-slip curves, and fracture energy of TRE-SWSSC interface. The main research factors included the erosion environment, the thickness of TRE composite, and the dry-wet cycles. The study showed that the failure mode of specimens with a small thickness of TRE composite are mainly the fracture and sliding of matrix in the free length of TRE. The failure pattern of the TRE-SWSSC interface with 20 mm thickness changed from the fracture and sliding of matrix in bond length of TRE to that in free length of TRE with the increase of dry-wet cycles. And the failure of specimens in immersion environment was interfacial peeling. The average bond strength of TRE-SWSSC interface increased with the thickness of TRE. After 270 days of environmental action, the interfacial average bond strength in the dry-wet environment was 15.94 % higher than that in the immersion environment. The load-slip curves were smoother for specimens with smaller TRE thickness, and the descending section of the load-slip curves became steeper with the increase of TRE thickness. The interfacial fracture energies of the specimens with different TRE thicknesses showed different growing trend with the dry-wet cycles. With the increase of the dry-wet cycles, the interfacial fracture energy of the specimens with a TRE thickness of 10 mm gradually increased, but the interfacial fracture energy of the specimens with a TRE thickness of 20 mm gradually decreased.