Durability of geopolymer concrete made of fly ash and slag

Geopolymer is a cementitious material known for its environmental benefits and comparable characteristics to the conventional ordinary Portland cement. Geopolymer concrete is a relatively new construction material that is yet to be regulated by the standards due to the high variability in the mix design. This paper thoroughly investigates the mechanical and durability properties of three types of geopolymer concrete in an attempt to improve knowledge in this area. In Type I, 4 concrete mixes were synthesised with high binder content (43%) and 3%-6% micro-silica. In Type II, 4 concrete mixes were made with moderate binder content (20%) and 0%-6% calcium carbonate. In Type III, one mix was designed with low binder content (15%). High compressive strength (71.6MPa) was achieved by the mix M1 of Type I. Type II and III mixes showed superior strengths than the comparable mixes from previous studies. It was found Type I mixes had a lower degree of reaction, making it less efficient in the strength development. Type II and III mixes performed similarly in the durability tests, which was mainly due to their similar binder contents.