Strength Development of Heat Cured and Ambient Cured Sodium Hydroxide Activated Fly Ash Based Geopolymer

Dicle Üniversitesi Fen Bilimleri Enstitüsü Dergisi, cilt.9, sa.2, ss.79-88, 2020 (Hakemli Dergi)

Compressive strength development of class F fly ash geopolymer activated by

sodium hydroxide was compared between initial heat curing at 75ºC for 24

hours and the ambient medium. Class F geopolymeric mortar was produced

with standard Rilem sand, sodium hydroxide, and water. Mortar mixtures

ratios were 3, 1, and 0.288 for sand, fly ash, and water, respectively. Some

samples were cured in laboratory conditions; some samples were heat cured

for 24 hours at 75ºC. Ambient curing medium result with non-measurable low

compressive strength up to 7 days, however significant strength development

observed in longer curing time up to six months. Heat curing developed higher

strength at all times than ambient curing did. It was concluded that heat cured

geopolymer samples could be utilized in construction materials, while

utilization of non-heat cured samples was not practical due to its longer curing

duration needs.