Evaluation of short- and long-term properties of heat-cured alkali-activated fly ash concrete

Abstract

Short- and long-term properties of alkali-activated fly ash concrete, namely, compressive, flexural and splitting tensile strengths, modulus of elasticity, Poisson ratio, early-age and drying shrinkage, creep and durability performance have been investigated in this paper. Blended ordinary Portland cement–fly ash concrete was used as a reference. The average compressive and flexural strengths of alkali-activated fly ash concrete at 28 d were 45 MPa and 5·8 MPa, respectively; drying shrinkage and creep values were about 360 and 200 microstrain, respectively, at 1 year. The total early-age shrinkage during the first 24 h of curing was lower for alkali-activated fly ash concrete at 1460 microstrain compared to 2800 microstrain for blended cement concrete. The use of this non-Portland cement containing material for producing precast concrete units can utilise high volumes of fly ash and potentially reduce the carbon footprint of the final product.