Damage Process of CFRP Composites-Concrete Interface Under Fatigue Loading at Low Temperatures

摘要

This paper presents the experimental and theoretical studies on the feasibility of using CFRP laminates for strengthening damaged reinforced concrete beams in cold environment. Experimental work includes investigation on fatigue strength, ultimate capacity and failure modes of repaired reinforced concrete beams in cold environment and room temperature. The study also includes investigation of thermal response of repaired plain concrete beams with CFRP laminates subjected to thermal cycles. Repaired reinforced concrete beams with CFRP laminates bonded with Sikadur 30 and Hysol 9330 adhesives were subjected to fatigue loading up to 1 million cycles in a cold environment (-20°C). The crack propagation was faster in beams tested in room temperature than those at cold temperatures. Analytical studies on the distributed shear forces and peeling forces of repaired reinforced concrete beams were carried out to analyze the interaction between the laminate and the concrete interface. The temperature distribution and strains developed by the temperature differential are determined and the analytical results compared with the measured values.