Chloride Ingress Resistance of Rice Husk Ash Based Green Concrete Composites Containing Steel Fibres

Abstract

Fibre reinforced concrete (FRC) is a conventional concrete mix that contains hydraulic cement, fine and coarse aggregate and discontinuous randomly distributed discrete fibre in concrete mix. Research has revealed that inclusion of fibre in concrete can enhance its performance characteristics in terms of durability, ductility, strength as well as energy absorption properties. Steel fibre concretes without Rice Husk Ash (RHA) have been successfully used for crack control in many structural applications. With the increasing amount of waste generation from various processes, there has been a growing interest in the utilization of waste in production of building materials to achieve potential benefits. This leads to sustainable, green and eco-friendly construction by reducing the price of components compare to disposing of the materials. This study examines the chloride resistance performance of green concrete composites containing steel fibre and 15% RHA. Four volume fractions of fibre from 0 to 2% at an interval of 0.5% and fibre length of 20 mm were used for CEM 1 (42.5 N) mixtures. The concrete was designed using the Department of Environment (DOE) mix design method to achieve a 28 days target strength of 30 N/mm2. Chloride resistance was assessed at 7, 28 and 56 days. The result shows that incorporation of steel fibre in RHA based concrete reduce the workability of concrete owning to its nature and affinity for water due to the presence of silica it contains. It was observed that incorporation of 1.0% steel fibre and 15% RHA in concrete provide a synergetic improvement on chloride resistance (durability) and strength when compared with control mix. The study recommends the utilization of steel fibre along with RHA in the production of a new alternative concrete composite that can resist chloride ingress in concrete composite.