Improving flexural toughness of foamed concrete by mixing polyvinyl alcohol-polypropylene fibers: An experimental study

In this study, the bending properties of polyvinyl alcohol-polypropylene fiber toughened foamed concrete were assessed by the three-point bending test. The flexural properties of specimens were studied in terms of load–deflection curve, failure mode, toughness, and toughening mechanism. The results showed that the mixture of various toughening materials had a synergistic effect on improving the bending property of polyvinyl alcohol-polypropylene fiber toughened foamed concrete. In addition, the increase of the contents of polyvinyl alcohol and polypropylene fibers could lead to the improvement of ductility, strength degradation, bending toughness, and bending degree of foamed concrete after reaching the peak. The influence of polypropylene fiber content on the specimen was greater than that of polyvinyl alcohol content. The toughened specimen had a single crack fracture mode. According to the scanning electron microscopy observations, the polyvinyl alcohol-polypropylene fiber mixture could provide an integrated network with satisfactory cracking resistance and form a variety of energy dissipation modes, thereby improving the bending toughness of the specimen.