Factors influencing strength and setting time of fly ash based-geopolymer paste

Adhitya Leonard Wijaya*, Januarti Jaya Ekaputri, Triwulan

*Corresponding author for this work

Research output: Contribution to journalConference articlepeer-review

28 Citations (Scopus)


In general, fly ash is often used as a binder in geopolymer mixture. In this paper, seven samples of fly ash were collected from five Indonesian power plants. The variation of fly ash may depend upon many factors. However, there is no standardization of fly ash used for geopolymer binder. This experiment was conducted to study and categorize fly ashes both by assessing their physical and chemical characters. All fly ashes were activated with alkali activator to prepare geopolymer paste. Ratio of fly ash to the alkali activator was kept constant at 65: 35. Compression test was conducted at three, seven, 14, 21, 28, and 56 days to identify the strength development of each sample. The result revealed that the content of CaO in fly ash affected the setting time and early strength development. In three days paste with CaO content more than 20% gain 54% of its 28-day strength. It is caused by both hydration and polymerization reactions. A range of Si to Al ratio contributed to the strength.

Original languageEnglish
Article number01010
JournalMATEC Web of Conferences
Publication statusPublished - 30 Dec 2017
Event6th International Conference of Euro Asia Civil Engineering Forum, EACEF 2017 - Seoul, Korea, Republic of
Duration: 22 Aug 201725 Aug 2017


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