AN INVESTIGATION INTO THE POST-CRACKING BEHAVIOUR OF WASTE COPPER WIRE FIBRE REINFORCED CONCRETE

Abstract

Cracks in concrete expand easily upon application of loads leading to its brittle failure. Fibers are used in concrete to prevent cracks formation. Copper wire has very slow corrosion, better mechanical properties, and ductility than most steel fibres. This paper studied the post-cracking behaviors of waste copper wire fibre (WCWF) reinforced concrete. The fibre contents were varied from 0 to 1.5% at an interval of 0.5% by weight of cement. The parameters tested were the toughness, residual strength factors, and equivalent flexural strength ratio. The load-deflection relationship revealed that the resistance to deformation of the concrete increases with an increase in WCWF. The toughness indices increased with an increase in WCWF contents. Toughness indices of 2.7, 4.3 and 7.0 were obtained for I 5 , I 10 and I 20 at 1.5% WCWF content respectively, which fall within the ranges specified by ASTM C 1018. The residual strength factor, R 5,10 increased from 16 at 0.5% to 32 at 1.5% WCWF content. Also, R 10,20 values of 18, 28 and 27 were obtained at 0.5, 1.0 and 1.5% WCWF respectively. The toughness at net deflection increased by 33.4% and 60.3% respectively. An equivalent flexural strength ratio of 56.71% obtained at 0.5% WCWF content implies that there is a post-peak flexural strength of 56.71% of the flexural strength at L150deflection. It is recommended that up to 1.5% of WCWF can be incorporated in the concrete to improve the resistance to deformation and energy absorption capacity of the concrete.