Effect of fly ash/silica fume ratio and curing condition on mechanical properties of fiber-reinforced geopolymer

Abstract

In this study, the effects of fly ash/silica fume (F/S) ratio and curing conditions on mechanical performance of fly ash based plain and steel fiber reinforced geopolymer (SFRG) was investigated. Plain geopolymer was prepared using NaOH solution of 14 molarity, Na₂SiO₃/NaOH of 2.5 and paste/fine aggregate of 0.36. For SFRG, the volume fractions of 0.5% and 1% were used. The F/S ratio was varied from 100/0 to 70/30. The specimens were cured under normal and accelerated conditions. Four experiments were carried out: flow, setting time, compression, and flexural performance tests. The results indicated that the addition of fibers enhanced the mechanical properties. The effect of F/S ratio depended strongly on the curing condition. Under ambient curing, the optimum F/S ratio of 90/10 was observed. For accelerated curing, the addition of silica fume provided negative effect on the mechanical properties. The optimum F/S ratio was observed in mix without silica fume.

Keywords:

• fiber-reinforced geopolymer
• curing condition
• fly ash/silica fume ratio
• flexural performance
• accelerated curing
• normal curing

Disclosure statement

No potential conflict of interest was reported by the author(s)

Additional information

Funding

This research is funded by King Mongkut’s University of Technology North Bangkok under contract no. no. KMUTNB-63-KNOW-024. The second author would like to acknowledge funding from Thailand Research Fund under contract no. DPG6180002.