Flexural behaviour of geopolymer concrete beams with hybrid natural–synthetic fibre reinforcement

Abstract

Archive excellence in the flexural stiffness initiates the exploration of fibre reinforcement in the construction industry. But the demand of cement and the processing complexity involved the synthetic fibres manufacturing techniques lead to the hazardous global warming. In this paper, an initiative was taken to implement the use of natural fibres in the geopolymer concrete structures by using natural-synthetic hybridization techniques. Natural basalt fibre was hybridized with synthetic steel fibres in various proportions in the geopolymer concrete structures and the workability, compressive strength, split tensile and flexural strength tests were carried out. From the results, it was observed that 1.5% addition of basalt fibre with 0.5% of steel fibre exhibited 45%, 27% and 12% improvement in the compressive, split tensile and flexural strength respectively than the plain geopolymer concrete. The compatibility between the steel and basalt fibres resulted in the enhanced post peak flexural behaviour which showed 37% improved modulus of elasticity and stiffness. As the basalt fibre possesses more tensile strength than the steel fibre, the hybridization of 1.5% basalt and 0.5% steel fibre exhibited better flexural and ductility properties than the steel fibre which will lead to the development of ductile geopolymer construction in the dynamic loading conditions.