An investigation into the mechanical behaviour of fibre-reinforced geopolymer concrete incorporating NiTi shape memory alloy, steel and polypropylene fibres

This paper studies the use of nickel-titanium (NiTi) superelastic shape memory alloy (NiTi-SMA), steel, and polypropylene (PP) fibres as reinforcement in geopolymer concrete (GPC) to improve the overall mechanical properties. NiTi-SMA, steel and PP fibres were added to the GPC at the fibre volume contents of 1.00%, 0.75% and 0.50% for steel and NiTi-SMA and 0.20%, 0.15% and 0.10% for PP. In this study, workability, compressive strength, splitting tensile strength, modulus of elasticity, static flexural strength and cyclic flexural tests were conducted to investigate the behaviours of steel fibre-reinforced GPC (SFRGPC), NiTi-SMA fibre-reinforced GPC (NiTi-SMAFRGPC) and PP fibre-reinforced GPC (PPFRGPC). The results showed that the mechanical performance of FRGPC increased with the increment of steel and NiTi-SMA fibres, but deceased with the increment of PP fibre. SFRGPC mixes exhibited the largest compressive strength (39.39 MPa), splitting tensile strength (5.36 MPa) and flexural strength (12.53 MPa), whereas NiTi-SMAFRGPC mixes presented the superior cyclic flexural performance which showed the smallest residue deformation and largest re-centring ratios in four cycles in comparison with SFRGPC and PPFRGPC mixes. (C) 2020 Elsevier Ltd. All rights reserved.