Effecting of steel fibers and fly ash on the properties of concrete

Abstract EN

In this research, the effect of the addition of fly ash particles with different weight ratios of 15%, 20%, and 25% as well as the addition steel fibers with different volume fractions of 0.25%, 0.75%, and 1.25% on the mechanical properties of concrete (compressive strength and modulus of rupture) was studied.

To carry out this research, ten concrete mixes were prepared, one of which is the reference normal concrete (without any additives), the others contain steel fibers and fly ash as additives with the mentioned volumetric and weight proportions.

For each type of concrete mix, three standard 150×300 mm cylinders and three standard prisms 100×100×500 mm were casted, water to cementing material ratio was fixed for all concrete mixes (W/cm = 0.435) and the superplasticizer was used with ratio of 0.98%-1.22% by weight of the cementitious material in mixtures that contain steel fibers and fly ash particles as a partial replacement of cement weight.

The results showed that the addition of fly ash particles had little effect on the mechanical properties of normal concrete, while the steel fibers had the greatest effect.

The highest increase in compressive strength and flexural strength compared with reference concrete was 61.60% and 78.84%, respectively in the volume fractions 1.25% of steel fiber.