Tensile properties of a novel fibre reinforced geopolymer composite with enhanced strain hardening characteristics

Abstract Strain hardening cementitious concrete is a type of fibre reinforced concrete with enhanced mechanical properties, including strain hardening and ductility. Geopolymer (cement-free) materials represent promising more sustainable alternatives to ordinary Portland cement. Heat treatment however is crucial when using geopolymer materials, to provide comparable mechanical properties to conventional concrete, and there are a number of practical limitations in the application of heat curing in large-scale structures. The main aim of this study is to develop and evaluate the mechanical properties of a novel, sustainable strain hardening fibre-reinforced geopolymer composite material, cured under ambient temperature and thus suitable for cast-in-place applications. In particular, the effect of incorporation of discontinuous fibres on the mechanical performance and on the microstructure of the composite geopolymer materials has been evaluated. Three different types of fibres have been examined in this study (PVA, steel, and glass) with various volume fractions and aspect ratios. The results indicate that room temperature cured, cement-free, strain hardening geopolymer concrete with superior deflection capacity can be produced using a ternary geopolymer binder mix reinforced by 2% PVA fibre or with 2% and 3% of 13 mm length steel fibre.