Experimental study on static and fatigue properties of CFRP reinforced concrete beams

Abstract

In order to solve the problem that steel corrosion seriously limits the service life of bridges, predecessors put forward the measure of using carbon fiber reinforced composite bar (CFRP) as stress bar. In order to study the static performance, fatigue performance and damage development of CFRP ribs, the static loading test of two mixed reinforced beams with different reinforcement ratios was carried out based on the static load test of pure reinforced concrete beams through three-point concentrated loading. The test results show that the CFRP rib beam works by the development process of balanced crack extension and fiber rupture; the deflection and strain of the test beam increase significantly in the initial stage of cyclic loading; as the number of load cycles increases, the crack growth rate becomes slower. And entering a relatively stable stage of development, and a large increase in the vicinity of the destruction; Under the same reinforcement ratio, the static load limit of composite reinforced beams is 0.95 times of that of pure reinforced concrete beams; the static load limit of 2FRP beams is 50% of that of 3FRP beams, but the fatigue life of 2FRP beams is 75 times of that of 3FRP beams. It can be seen that appropriate reinforcement ratio can effectively improve the service life of specimens. On the basis of the test, some suggestions on the design of CFRP reinforced concrete beams are put forward. The research results can be used for reference in the follow-up study.