Comparison of flexural property between high performance polypropylene fiber reinforced lightweight aggregate concrete and steel fiber reinforced lightweight aggregate concrete

The main purpose of this study was to investigate the flexural property of high performance polypropylene fiber reinforced lightweight aggregate concrete (HPPLWC) and steel fiber reinforced lightweight aggregate concrete (SFLWC). Firstly, two widely used standards (ASTM C1609 and JSCE SF-4) were used to evaluate their flexural toughness. Meanwhile, the advantages and disadvantages of these two methods in evaluating the flexural toughness of HPPFLWC and SFLWC were analyzed. Then, a new toughness evaluating method specified in JG/T 472-2015 was used. In addition, the optimal fiber content was proposed according to the flexural toughness of fiber reinforced lightweight aggregate concrete. The results showed that the optimal high performance polypropylene fiber (HPPF) content and steel fiber (SF) content were 1.1 vol% and 2.0 vol% respectively. SFs performed better on improving the equivalent initial flexural strength and equivalent residual flexural strength than HPPFs. HPPFs' effectiveness on post-peak behavior was higher than its effectiveness on pre-peak behavior. However, SFs performed better on pre-peak behavior than its effect on post-peak behavior.