An Experimental Study On Slag/Fly Ash-Based Geopolymer Concrete
This research outlines an experimental program to investigate material properties of one type of geopolymer
concrete, slag/fly ash-based geopolymer concrete. Slag/fly ash-based geopolymer concrete uses slag and fly ash to entirely
replace portland cement as the cementing material. In this study, slag and fly ash were obtained from a local ready-mix
concrete plant in the Midwest of the United States. A number of pre-test mixes of geopolymer cement were made to determine
suitable mix proportions. It was found that workability of the geopolymer cement studied was highly influenced by the
slag-to-fly ash ratio. Three geopolymer concrete mixes with varying slag-to-fly ash ratios were produced and tested to
determine slump, air content, unit weight, 7 and 28 day compressive strength, and flexural strength. Results showed that all the
three mixtures investigated in this study possessed compressive strength, air content, and unit weight comparable to those of
ordinary portland cement concrete. Furthermore, the studied geopolymer concrete exhibited high early strength, compared to
that of ordinary portland cement concrete. However, the flexural strength of the studied geopolymer concrete was lower than
that of ordinary portland cement concrete.
Index Terms- concrete, geopolymer, fly ash, slag.