Relationship between Compressive, Flexural and Split Tensile Strengths of Waste Copper Wire Fiber Reinforced Concrete

Abstract

Concrete has low tensile strength, narrow ductile range and low crack resistance. Micro cracks in the concrete propagate quickly under loading, leading to brittle behaviour of the concrete. These cracks expose steel reinforcement to agents of corrosion. Adding steel fibres reduces the damage, but over a long period, the steel fibres corrode. This study used waste copper wire as fibre reinforcement in concrete to investigate the relationship between compressive, flexural and split tensile strengths. Grade 25 concrete was produced and cured for 7, 14 and 28 days before testing. One millimetre in diameter copper wire was used in the study. The fibre volume used was 0.5, 1.0 and 1.5%, respectively. The samples were tested for compressive, flexural and split tensile strengths. The results indicated a general increase in compressive, flexural and split tensile strengths of the concrete with an increase in waste copper wire fibre contents. Maximum compressive strength of 34.58 N/mm 2 was obtained at 1.5% fibre content and 28 days of curing. Flexural strength increases from 4.36 N/mm 2 at 0% fibre content and seven days curing to 6.68 N/mm 2 at 1.5% fibre content and 28 days curing. The split tensile strength increased fibre content from 2.72 N/mm 2 at seven days to 4.39 N/mm 2 at 28 days of curing. Mathematical models were produced for the relationships between compressive, flexural and split tensile strengths. The models have R 2 values greater than 70%, and the higher the value of R 2 , the better the model fits the data. This indicates that the model’s predictors influenced the variations in the responses.