Simulation Of Corrosion-induced Concrete Spalling And Its Effects On Shear Behavior Of RC Beams

Reinforced concrete(RC)structures are widely used in infrastructure construction,such as building,highway and so on which are prone to steel corrosion under unfavorable environment.Corrosion not only causes the loss of steel cross-section,degrades the bond between steel and concrete,but also causes the damage of concrete,even the spalling of concrete cover.The concrete damage has a significant influence on shear strength,but there are few related researches.Therefore,this paper studies the influence of rust expansion,spalling of concrete cover,and the shear capacity of corroded RC beams through experiments and finite element analysis.The main contents are shown as follows:(1)Rapid corrosion experiments are carried out on fourteen RC beams.According to cracks observation and core sampling,the development rule of concrete cover damage is given.Furthermore,the influence of steel corrosion and concrete cover damage on shear failure,deflection deformation and ultimate bearing capacity of concrete beams is clarified by corroded concrete shear performance experiments.(2)The non-uniform rust expansion model in concrete with random aggregate distribution is established.It focuses on the interface between aggregate and mortar,the random distribution of aggregate and the non-uniform corrosion of steel reinforcement.Based on this model,the effects of corrosion rate,diameter of reinforcement,thickness of concrete cover and location of reinforcement on concrete damage and spalling are analyzed.Then,the key factors affecting the spalling of concrete are condensed,and a simplified prediction model for the cracking of concrete cover of corroded concrete is presented.(3)The finite element simulation method of RC beams shear capacity considering rust expansion is proposed.This method adopts simplified prediction model.Also,the corrosion-induced steel loss,degradation of material performance and bond performance is considered in this method.On this basis,the influences of corrosion degradation and concrete section damage on the shear strength of concrete beams are analyzed.