Effect of salient parameters on fresh properties and compressive strength of self-compacting geopolymer concrete

Due to growing environmental concerns of the cement industry, alternative cement technologies have become an area of increasing interest. An effort in this regard is the development of self-compacting geopolymer concrete. Self-compacting geopolymer concrete is an innovative type of concrete that might not require vibration for placing it and could be produced by complete elimination of ordinary Portland cement. This paper describes the results of an experimental study carried out to investigate the effect of salient parameters on fresh properties and compressive strength of selfcompacting geopolymer concrete (SCGC), prepared by using low-calcium fly ash as base material and combination of sodium hydroxide and sodium silicate as alkaline activator. The experiments were conducted by varying the amount of extra water, curing time, curing temperature, dosage of superplasticizer and concentration of sodium hydroxide. Test methods such as Slump flow, V-Funnel, L-box and J-Ring were used to evaluate the self-compactability of fresh concrete. Compressive strength test was performed at the ages of 1, 3, 7, and 28 days to examine the strength development of hardened SCGC mixes. The results of the quantitative measurements and visual observations indicate that the workability of fly ash-based SCGC is dependent on amount of extra water and dosage of superplasticizer. It is also found that sodium hydroxide concentration also affect the fresh properties but to a lesser extent. The test data also show that longer curing time and curing the concrete specimens at higher temperatures will result in higher compressive strength.