Contribution of lightweight self-consolidated concrete (LWSCC) to shear strength of beams reinforced with basalt FRP bars

摘要

To date, the shear contribution of lightweight self-consolidating concrete (LWSCC) members reinforced with basalt fiber-reinforced polymer (BFRP) bars (LWSCC-BFRP) has not yet been investigated. Therefore, the anticorrosion properties of BFRP bars combined with the advantages of LWSCC motivated this research to assess the behavior of such members under shear. Eight beams cast using LWSCC and normal-weight concrete (NWC) reinforced with BFRP or steel bars were prepared and tested up to failure. The specimens had a total length of 3100 mm and concrete cross section of 200 mm in width and 400 mm in depth. The influence of two different types of BFRP bars of comparable quality and commercially available (sand-coated basalt and helically grooved basalt) on shear capacity was assessed. The tested beams included five beams reinforced with BFRP bars, one beam reinforced with steel bars, and two beams constructed using NWC for comparison purposes. The experimental results indicate that the adoption of LWSCC allowed for decreasing the self-weight of the reinforced concrete (RC) beams (density of 1800 kg/m(3)) compared to NWC. Test results show that the concrete shear capacity of the LWSCC beams increased as did the axial stiffness of the longitudinal BFRP reinforcing bars. The test results were compared with the shear capacities predicted using the provisions in several standards. Using a 0.75 concrete density reduction factor in the CSA 2012 shear equation to consider the influence of concrete density yielded a more accurate value for the concrete shear capacity. In addition, using a 0.8 concrete density reduction factor in the ACI 2015 design equation yielded an appropriate degree of conservatism compared to the NWC beams.