Bending properties of fine-grained concrete composite beams reinforced with single-layer carbon/polypropylene woven fabrics with different weave designs and thread densities

The aim of this study is to evaluate the effect of thread density and weave design on the bending properties of fine-grained concrete beams reinforced with single layer carbon/polypropylene woven fabric. In this study, at first, fabrics were woven with two types of design (plain and twill) and four different thread densities. Then, they were compounded into fine-grained concrete as a beam. After 4 weeks, the bending properties of all the samples were tested using four-point bending test method. The bending properties of these composite samples were evaluated using different parameters including the load at the elastic zone (limit of proportionality [LOP]) as well as the highest-peak point (modulus of rupture), toughness values, and toughness indices at the specific deflections. New parameters namely: toughness value and toughness index at the highest-peak point were also suggested in this study. The results showed that the bending load of concrete beams reinforced with plain fabric at the elastic region (LOP point) is identical to that of simple concrete beam whereas concrete beams reinforced with twill fabric exhibited lower value. Also, increasing thread density increased the bending load at the composite failure point while the effect of weave design was not significant. It is also indicated that the toughness properties of concrete composite beams have been improved with a denser carbon/polypropylene fabric particularly at higher bending deflections whereas the weave design did not show any significant effect and only influenced on toughness properties at small deflection values. The obtained results of this work suggest that concrete composite beams reinforced with carbon/polypropylene woven fabrics on average are 6.5–40.75 times tougher than simple concrete beams.