DAMAGE RESISTANCE OF REINFORCED CONCRETE STRUCTURES THAT UTILIZE HIGH PERFORMANCE HYBRID FIBER REINFORCED (HYFRC) COMPOSITES

The paper focuses on the effect of multi-scale crack control from the micro-to the macrolevel in hybrid fiber reinforced concrete (HyFRC) composites on performance enhancement and damage resistance when concrete structures are subjected to corrosion as well as seismic loading conditions. Deterioration of reinforced concrete structures is intimately related to cracking and the rate at which water and aggressive agents are able to penetrate the concrete. For the corrosion study, flexural beam specimens containing steel reinforcing bars were prepared with plain concrete and HyFRC matrices and tested under equivalent, cyclic load based demands and corrosion is initiated by ponding salt water on the tensile surface. Corrosion initiation and propagation rates were determined from periodic polarization resistance and galvanic current flow measurements. Longer times to corrosion initiation and lower active corrosion rates were observed in the HyFRC beam specimens when compared to the reinforced specimens containing plain concrete matrices. To investigate the effect of HyFRC on seismic performance and post-earthquake damage resistance, 1:4.7 scale HyFRC bridge columns were tested statically under uni-directional cyclic loading. Compared to conventional reinforced concrete columns of same dimensions the HyFRC columns exhibit superior damage resistance and better load carrying capacity at half their transverse reinforcing ratio.