the experimental assessment of the effect of polypropylene fibers on the improvement of nano-silica concrete behavior

In this study, the effect of water-cement ratio on the mechanical properties (compressive, abrasion, tensile, exural strength, and permeability) of nano-silica concrete reinforced with polypropylene fibers is evaluated. the specimens contain 4% of nano-silica, 0.30, 0.35, 0.40, 0.45, and 0.50 of water-cement ratios, and 0, 0.10, 0.15, 0.25, and 0.35 percent volumes of polypropylene fibers. other design features remain fixed in all concrete samples. the results of the experiments showed that with decreasing the ratio of water to cement from 0.50 to 0.30, all the mechanical properties of the concrete were improved. in addition, the test results showed a significant increase in mechanical properties improvement of concrete by using polypropylene fibers. tensile strength, exural strength, and abrasion resistance of concrete increased up to 22%, 40%, and 27%, respectively, for the 28-day age specimens. in addition, a considerable reduction of hydraulic conductivity coecient to 51% indicates high durability of these types of concrete. compressive strength showed increment rates of 22%, 15%, and 14% for 7-, 28-, and 90-day age specimens, respectively.