Drying Shrinkage of Heat-Cured Fly Ash-Based Geopolymer Concrete

Fly ash-based geopolymer concrete is manufactured without using portland cement at all. This type of concrete has environmental benefit as it has very low of greenhouse gas emission compared to that resulted from the production of portland cement. In addition, it also utilizes waste or by-product material that makes it more environmentally friendly. This paper presents the study of drying shrinkage of heat-cured fly ash-based geopolymer concrete. Geopolymer concrete in this study used low-calcium fly ash as its source material, alkaline solution and aggregates normally used for ordinary portland cement concrete. Four series of test specimens with different compressive strength were prepared to study the drying shrinkage of this concrete. The test results were then compared with the calculated results of drying shrinkage as predicted by Gilbert Method which is normally used for ordinary portland cement concrete. Test results shows that the heat-cured fly ash-based geopolymer concrete undergoes very low drying shrinkage. The drying shrinkage strain at one year as calculated using Gilbert Method is much higher, about five to seven times, compared to the measured drying shrinkage strain from the tests.