Mechanical Properties of Fibre-Reinforced High Strength Concrete

Abstract

The increased use of high strength concrete in structural applications dictates the need to enhance its brittle behaviour under compressive and tensile loads. An experimental programme has been conducted to investigate the effects of introducing polypropylene fibres into higher strength concrete applications. Different fibre volume fractions were used in the study. Three types of concrete grades were cast. Uni-axial compressive and splitting cylinder tests were conducted. Longitudinal, transverse and volumetric strains were monitored and reported at different stress levels during testing. Material properties including peak compressive stresses for both cylinders and cubes, splitting cylinder tensile strengths, elastic moduli and Poisson's ratios were determined.The study revealed that polypropylene fibres significantly enhanced the tensile properties of higher strength concretes, increased the ductility under compressive loads, reduced transverse deformations however reduced the peak attainable strength under compressive loads. A model for calculating the tensile strength of concrete as a function of both the concrete grade and the fibre volume fraction has been developed. The model shows excellent agreement with the experimental results.