THEORETICAL ANALYSIS ON FLEXURAL BEHAVIOR OF REINFORCED ULTRA HIGH TOUGHNESS CEMENTITIOUS COMPOSITE MEMBERS

The injurant such as vapor, carbon dioxide, chloride may lead the corrosion of steel bar if there is any macro-crack in concrete structures. The possibility of corrosion should be evidently reduced in respect that ultra high toughness cementitious composite (UHTCC) can effectively control crack width, so that the durability will be improved markedly, compared to reinforced concrete structures. UHTCC shows high toughness and pseudo strain-hardening behavior under tension. Therefore, it can undertake a part of the tension load. In order to logically design the reinforced UHTCC members under bending load and saving steel products, the tension load carrying capacity of UHTCC in tension region should be considered. The investigations on reinforced UHTCC flexural members have been carried out, including theoretical analysis of bending members, experimental research on long beams without web reinforcement, validation and comparison between experimental and theoretical results, the analysis of crack control and simplified calculation methods of load bearing capacity. According to pseudo strain-hardening behavior of UHTCC under tension, a bilinear model under compression and plane-section assumption, the paper presents the theoretical analysis on reinforced UHTCC flexural members, such as the analysis of the internal force at different stage, confirmation of height of compression zone, the moment-curvature relationship and calculation of mid-span deflection.