HYBRID STEEL FIBER REINFORCED CONCRETES: EFFECTS OF ELEVATED TEMPERATURE AND WATER RE-CURING ON THE MECHANICAL PERFORMANCE

This study investigated the effect of elevated temperatures and water re-curing on the mechanical response of hybrid steel fiber reinforced concretes. The first part of the study examines the effect of various steel fiber hybridizations on the compression, tension, shear and fracture behavior of fiber reinforced concretes at room temperature. The second part details the effects of elevated temperature and water re-curing on the compression performance and fracture process of hybrid steel fiber reinforced concretes. The results indicated an increase of the damage as the temperature increased. However, a considerable reduction of damage was obtained after water re-curing. Exposure to temperatures exceeding 200 °C had a negative impact on fracture toughness. The exposition to elevated temperatures and water re-curing modified the fracture process of hybrid fiber reinforced concrete. For temperatures above 200 °C, the branching fracture appeared around the peak load level. Water re-curing reduced the branching effect and prevented the formation of multiple cracks in thermally damaged hybrid fiber reinforced concrete.