CARBON FRP CONFINED CONCRETE ELEMENTS UNDER AXIAL LOAD

The use of FRP (Fiber Reinforced Plastic) reinforcement is growing as the deterioration of old structures, the corrosion problems and the need for rehabilitation and strengthening of existing structures (especially in high seismic regions) becomes urgent. Carbon FRP material has been proved to be more efficient than other composites when applied to concrete columns as an external reinforcement. Due to its enhanced durability characteristics compared to glass or aramid and additionally due to its relatively high E-modulus, carbon FRP shows a higher confining performance. The behavior of 22 cylindrical 200 mm x 320 mm specimens (height to diameter ratio: 1.6) that are externally wrapped by carbon FRP sheets in low volumetric ratios (0.23% - 0.7%) is presented. The specimens are subjected under axial monotonic load until their failure. Carbon FRP confinement, even in low volumetric ratios, seems to considerably increase strength and especially ductility of concrete. The measured absorbed energy of the composite system points out that the energy absorption capacity of concrete is significantly enhanced when concrete is confined by carbon FRP sheet. For the covering abstract see ITRD E123557.