PERFORMANCE OF STEEL FIBER EXTRACTED FROM OLD WASTE TYRES ON MECHANICAL PROPERTIES OF CONCRETE FOR RIGID PAVEMENT CONSTRUCTION

Abstract

The application of Waste Recycled Steel Fibers (WRSF) extracted from waste tyres in fiber-reinforced concrete production has great benefits in civil engineering. Thus, this creates a need to study the appropriate length and dosages of recycled steel fiber in fiber-reinforced concrete. In this experimental research, the effects of varying lengths (5cm and 10 cm) and dosages (1, 1.5, 2, 2.5, and 3%) of WRSF on various mechanical properties of fiber-reinforced concrete for rigid pavement construction were studied. The aggregates were taken from a stockpile, commercially available cement Dangote Ordinary Portland Cement (OPC), and potable water. Non-probable sampling techniques were adopted to collect extracted waste steel tyres. The quality test for sand (fine) and coarse aggregate satisfies the requirements specified in the ASTM. The concrete mix design was done in two categories; the first was a control mix concrete and the second was the experimental mix concrete with the addition of steel fibers with varying lengths (5cm and 10 cm) and dosages (1, 1.5, 2, 2.5, and 3%) of WRSF in concrete (percentages were determined by density for each fiber). The mix ratio of cement: sand: aggregate (1:2:3) with a constant water-to-cement ratio of 0.53 was used throughout this investigation. The outcome showed that the fiber fraction with 1.5% and 10cm of fiber had the maximum compressive strength which was 45.59 MPa, while for the fraction with 1% and 5cm of fiber, the maximum compressive strength was 43.85 MPa. The flexural strength had a maximum value of 5.88 MPa at 3% fiber content for 5cm fiber and 5.09 MPa at 3% for 10cm of fiber. The maximum tensile strength attained was 4.74 MPa and 3.50 MPa at 3% WRSF for 5cm and 10cm of fiber, respectively. The strain value had a maximum value at 3% for both 10cm and 5cm of fiber which were 0.53 and 0.6 respectively. The concrete strength which was obtained with the addition of steel fiber showed reasonable improvement in compressive, indirect tensile, and flexural strength. However, as the percentage of WRSF increased, the workability of concrete reduced.