The Effect of Aspect Ratio and Volume Fraction on Mechanical Properties of End of Life Tyre Steel Fibre Reinforced Concrete

Abstract

The utilization of end-of-life tire steel fibers (ELTSFs) to produce greener concrete by reducing the amount of solid waste was investigated in this research. Steel fibers are incorporated into concrete to improve its mechanical and durability properties. This paper reports the effect of fiber length and volume fraction (Vf) of ELTSFs in concrete. The fresh and mechanical properties examined were workability and compressive strength of six mixes of grade 25 (25 N/mm²) with varying fiber lengths of 10 mm, 20 mm, 30 mm, 40 mm, 50 mm, and 60 mm; representing aspect ratios of 10.87, 21.74, 32.61, 43.48, 54.35, and 65.22 respectively. For each fiber length, concrete with five volume fractions (0.5%, 0.75%, 1.0%, 1.5%, and 2.0%) were produced and cured for 3, 7, 14, 21, 28, and 60 days by water immersion. For all resulting concrete, slump value and compressive strength were investigated. The results show that workability decreases with an increase in the fiber length and volume fraction. Concrete with a 10 mm length and a volume fraction of 0.5% produced concrete with the highest slump. The concrete mix with a 60 mm fiber length and a 1.0% volume fraction at 60 days of curing regime gives the optimum compressive strength, enhancing it by 9.85% compared to the reference concrete. The regression model developed for the compressive strength showed a very good relationship between the response and the regressor variables. The coefficient of determination (R²) is 0.8894, and all the model terms' P-values are less than the alpha value (0.05).