Experimental study on flexural performance of corroded reinforced concrete beams after fire exposure
In order to study the residual mechanical properties of existing concrete structures after fire,9 reinforced concrete beams were designed and fabricated.The corroded concrete beams with different corrosion degrees(target corrosion degree was 5％and 15％)were obtained by electrochemical accelerated corrosion tests.The fire tests were conducted for different fire durations(1 h and 2 h)according to the ISO834 standard heating curve.Finally,the static loading tests were conducted on all concrete beams.The results show that the failure process and mode of the corroded reinforced concrete beams are similar to those of the ordinary concrete beams,which shows bending failure mode.Compared to ordinary beams,their load-deflection curve will shift downwards and exhibit characteristics of working with cracks and failure stages,and the deflection deformation is also greater.For concrete beams that have undergone different fire exposure time,steel corrosion significantly reduces their yield load,but the effect of steel corrosion on the ultimate load of concrete beams at room temperature is relatively small.The effect of fire significantly reduces the ultimate bearing capacity of concrete beams.The variation pattern of residual bearing capacity of slightly corroded beams after fire is similar to that of non corroded beams,and the corrosion of steel bars hardly weakens the bending bearing capacity of the components.For severely corroded beams,due to the weakening of the cross-section caused by corrosion and the influence of rust expansion cracks,the highest temperature experienced by corroded concrete beams under fire is higher,and their residual ultimate bearing capacity accelerates to decrease after the fire.The residual ultimate bearing capacity of concrete beam with corrosion rate of 13.5％for the same fire exposure time is 15.9％lower than that of concrete beam with corrosion rate of 6.2％.
NETL
NSTL
万方数据
维普
