Novel one-part fly ash alkali-activated cements for ambient applications

Abstract

Alkali-activated cements utilising fly ash can be a low carbon alternative to Portland cement. However, fly ash alkali-activated cements require elevated temperature curing and has cost plus environmental implications due to the use of strong alkali solutions. Unclassified fly ash, silica fume, calcium hydroxide and sodium carbonate were used to develop novel one-part fly ash alkali-activated cements. Cured at ambient conditions, the developed cements gained compressive strength up to 11.0 and 44.2 MPa at 3 and 28 days respectively. Microstructural investigations revealed that cation exchange reaction between the activators was the key element in microstructural and strength development of the cements. The developed novel fly ash alkali-activated cements have at least 50% lower impact on global warming than highly blended Portland cements.