Performance of Polymer Modified Polypropylene Fiber Reinforced Concrete

Abstract

Abstract

The fiber reinforced concrete (FRC) is a composite material essentially consisting of conventional concrete reinforced by random dispersal of short, discontinuous and discrete fibers of specific geometry. The conventional plain concrete possesses high compressive strength, low tensile strength, poor impact strength, ductility, and little resistance to cracking and poor resistance to chemical attack. The presences of micro-cracks at the mortar aggregate interface are responsible for the inherent weakness of plain concrete. This weakness can be removed by inclusion of fibers in the mix. The fibers help to transfer loads at the internal micro-cracks. Different types of fibers are investigated and utilized for different applications. Each type of fiber has its own characteristic property. In this study, polypropylene fiber is used. Polypropylene fibers are randomly distributed in concrete and arrest the propagation of micro-cracks and results in increasing flexure, compression and bond strength. In the present work an attempt is made to study the behaviour of polymer modified polypropylene fiber reinforced concrete. For this work, M20 grade is used and the concrete is modified with 10% SBR Latex polymer. Fiber content is varied from 0 to 0.3 at an interval of 0.05 for low volume fraction and fiber content 0 to 5% at an interval of 1% by weight of cement for high volume fraction. Polypropylene fibers of 25 µm diameter and length 10 mm are used. Effect of this fiber on various strengths of concrete are studied. Various strengths considered for investigation are compressive strength, flexure strength, split tensile strength, and bond strength. Cube of size 150×150 mm, Beam of size 150×150×700 mm and Cylinder of size 150mm radius and 300 mm length are used. All specimens were water cured up to 28 days and tested destructively and non-destructively. The investigation shows decrease in workability as fiber content varied from 1–5%. The Poisson’s ratio is found to vary within the specific limit. Relations are developed on the behaviour of concrete in various states of stress with respect to Vf, and Fck.