The influence of curing method on properties of laterite soil based geopolymer cement

Abstract

The paper investigates the effect of curing conditions on the properties of laterite soil-based geopolymer cement. In the experimental testing, calcined laterite soil was used as a solid precursor in the preparation of geopolymer cement. Standard size prismatic geopolymer specimens were prepared and subjected to four curing methods, including open air curing and courses of combined open-air curing and oven curing. The prisms were tested at 3, 7, and 28 days to determine the effect of curing methods on the flexural and compressive strengths. The crushed prisms were further pulverised and analysed to investigate the microstructure, elemental composition, mineralogical phases, chemical bonding, and thermal behaviour. The findings showed that the highest strength at 28 days was obtained with the air curing method. However, the curing methods involving an oven curing course resulted in the highest early strength at 3(early strength) and 7 days.

HIGHLIGHTS • Laterite soil calcined at 700ºC is used as a geopolymer precursor. • The degree of geopolymerization is clearly obsetved in air curing and oven curing. • Air curing before oven treatment improves Si, Al, and Fe dissolution in laterite soil. • Higher compressive strength was achieved on air curing. • Curing age significantly affects the strength of air-cured samples, but not oven-cured ones.