The effect of using inorganic silica powder on the mechanical properties of concrete containing glass fibers

The high consumption of concrete in the world has caused that to improve of concrete technology.In order to have a denser concrete and modifying the structure of concrete, silica powder can be used toimprove the quality of concrete. In addition, to solve the weakness of concrete in tensile, a number ofresearch has been performed on using fiber in concrete to increase the efficiency of tensile strength. Inthis study, silica powder as a filler has been used as partial replacement of sand by ۲.۵ to ۱۰ percent andglass fibers by ۰.۲ percent of the concrete volume. To study the properties of concrete in fresh andhardened state, slump test, splitting tensile and compressive strength tests and ultrasonic pulse velocitytest has been carried out. Based on the results, in concrete with or without fiber, as it expected the slumphas been continues reduced by increased the amount of silica powder. The use of silica powder in nonfiberconcrete has reduced the compressive strength. Due to the densification of concrete by using silicapowder, the tensile strength has increased by an average of ۱۸%, which indicates the role of silicapowder in the quality of concrete, and the results obtained by ultrasonic test confirm this phenomenonas well. According to this study, with the addition of glass fibers in concrete, an increase in compressive,and splitting tensile strengths can be expected in concrete with inclusion of silica powder. Optimumsilica powder replacement level for sand was found to be ۵% by weight of sand.

Keywords:

Density , Fiber , Glass , Silica powder , Slump , Ultrasonic.