Experimental investigation of mechanical properties of GGBS-FA-SF blended geopolymer concrete at elevated temperatures

Geopolymer has excellent mechanical properties at elevated temperatures, but geopolymer concrete may not be so because of the large difference in thermal properties between geopolymer and aggregate which could lead to substantial thermal stresses when they are in a high temperature environment. In this paper we present an experimental investigation on the mechanical properties of GGBS-FA-SF blended geopolymer concrete with and without steel fibres at elevated temperatures. The influences of exposure temperature, coarse aggregate and steel fibre on the failure mode, compressive strength, elastic modulus, peak strain, and ductility of the geopolymer mortar and geopolymer concrete are examined. Based on the experimentally obtained data, empirical temperature-dependent stress-strain constitutive equations are also proposed, which can be used for the fire safety analysis and design of geopolymer concrete with and without steel fibres.