Tensile and Compressive Strength Investigations of Ordinary Concrete and Pozzolanic Concrete and the Effect of Polypropylene on Them

Abstract

Fibers increase cohesion, increase tensile strength, reduce cracks, and increase the softness of concrete. The type of fibers used in concrete and their size depends on the type of concrete used and tensile strength. Fibers used in concrete can be glass, steel, or polymer fibers. Polypropylene fibers are economically efficient, and considering their favorable properties, in this research we examine the effect of these fibers on ordinary concrete and pozzolanic concrete. After preparing the necessary materials, which include cement, water, stone materials, and lubricants, it is necessary to prepare the additives required for concrete, which include polypropylene fibers and metakaolin pozzolan. The samples made in this research include control sample S and sample A1 with 0.2% by weight of polypropylene fibers and 5% by weight of metakaolin pozzolan, sample A2 with 0.2% by weight of polypropylene fibers and 10% by weight of metakaolin pozzolan, sample A3 with 2.2 0% by weight of polypropylene fibers and 10% by weight of metakaolin pozzolan, sample B1 has 0.5% by weight of polypropylene fibers and 5% by weight of metakaolin pozzolan, sample B2 has 0.5% by weight of polypropylene fibers and 5% by weight of metakaolin pozzolan, sample B3 has 0.5% by weight of polypropylene fibers and 15% by weight of metakaolin pozzolan, sample C1 has 1% by weight of polypropylene fibers and 5% by weight of metakaolin pozzolan, sample C2 has 10% by weight of polypropylene fibers and 10% by weight of metakaolin pozzolan, sample C3 has 1% by weight of polypropylene fibers and 15% by weight of metakaolin pozzolan. The use of polypropylene fibers reduces the compressive strength. It increases the tensile strength of the samples, and the use of high percentages of pozzolan improves the compressive strength and tensile strength.