TIME-DEPENDENT BEHAVIOUR OF A CLASS F FLY ASH-BASED GEOPOLYMER CONCRETE
The main purpose of this research is to study the time dependent behaviour of a geopolymer concrete. The geopolymer binder is composed of 85.2% of low calcium fly ash and only 14.8% of GGBFS (Ground Granulated Blast Furnace Slag). Both drying shrinkage and creep are studied. Tests were performed on small size specimens according to Australian Standard AS1012.13 for shrinkage and AS1012.16 for creep. Different curing regimes at elevated temperature were used. All experimental results were compared to Australian Standard AS3600 predictions. Curing regime plays an important role on both creep and drying shrinkage of class F fly ash based geopolymer concrete. A minimum of three days at 40 0 C or one day at 80 0 C is required to obtain final drying shrinkage strains similar or less than the one predicted by AS3600 for OPC concrete. Creep strains are reduced of about 70% compared to predicted OPC concrete values when the geopolymer concrete was cured for three days at 40 0 C. After 7 days at 80 0 C, creep strains were very low.