Constitutive Behaviour of Lateral Ties Confined Polyolefin Fibre Reinforced Concrete under Monotonic Axial Compression

Abstract

In this investigation, the combined effect of spacing of lateral ties and volume fraction of polyolefin fibres was studied both experimentally and analytically from the point of deformability characteristics of concrete. Low modulus synthetic fibers such as polyolefin based fibers, it is shown that polyolefin fibers with sufficient tensile strength can successfully enhance the mechanical properties of concrete. The mechanism of delaying and arresting the progressive internal cracking from transition zone to the matrix by the fibres can be made use in passive confinement of concrete. Such concrete was termed as polyolefin fiber reinforced concrete (PFRC). In this study the confinement effectiveness of polyolefin fibres of volume fractions 0.3%,0.5%,0.7%,0.9% and 1.2% in addition to lateral ties of spacing 290mm, 145mm and 75mm on concrete prisms of size 150 ×150 ×300 mm were investigated. Such concrete is termed as confined polyolefin fiber reinforced concrete (CPFRC).This paper presents an analytical model(profile) for predicting the constitutive behaviour of CPFRC based on the experimental and analytical results. A total of seventy two prisms of size 150 ×150 ×300 mm were cast and tested under strain control rate of loading. The increase in strength and strain of CPFRC were used in formulating the constitutive relation. The results of the testing demonstrate the behavioral differences between plain and CPFRC and the ability of the synthetic macro fiber to be used as secondary reinforcement in seismic resistance applications.