Process Development of Fly Ash-Based Geopolymer Mortars in View of the Mechanical Characteristics

Hatice Öznur Öz, Neslihan Doğan-Sağlamtimur, Ahmet Bilgil, Aykut Tamer, Kadir Günaydin

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15 Citations (SciVal)


This study aimed to determine the effects of design parameters, including the liquid/solid ratio (L/S), Na2SiO3/NaOH weight ratio, and curing temperature, on class F fly ash-based geopolymer composites. For this purpose, two disparate sources of fly ash were supplied from Çatalağzı (FA) and İsken Sugözü (FB) Thermal Power Plants in Turkey. Two different L/S ratios of 0.2 and 0.4 were used. The Na2SiO3/NaOH ratios in the alkaline solutions were 1, 1.5, 2, 2.5, and 3 by weight for each type of geopolymer mixture. Then, 40 different mixes were cured at two specific temperatures (70 °C and 100 °C) for 24 h and then preserved at room temperature until testing. Thereafter, the physical water absorption properties, apparent porosity, and bulk density were examined at 28 days on the hardened mortars. Additionally, compressive and flexural tests were applied to the geopolymers at 7, 28, and 90 days. It was found that the highest compressive strength was 60.1 MPa for the geopolymer manufactured with an L/S of 0.2 and Na2SiO3/NaOH ratio of 2. Moreover, the best thermal curing temperature for obtaining optimal strength characteristics was 100 °C for the FB.
Original languageEnglish
Article number14112935
Issue number11
Publication statusPublished - 29 May 2021

Bibliographical note

This study is a part of the project “Development of Eco-Friendly Composite Materials based on a Geopolymer Matrix and Reinforced with Waste Fibers”, funded by the European Commission, within the 7th Framework Program for Research and Technology Development (FP7), Topic #02: Waste Management, Recycling, and Urban Mining (Project No. ELAC2015/T02-0721), under the ERANet-LAC: Latin America, Caribbean, and European Union; and supported by a grant from the Turkish Scientific and Technological Research Council of Turkey (TÜBİTAK). The Turkish project number is 116Y549. Article Processing Charges was funded by Imperial College London Open Access Fund.

Data Availability Statement
No new data were created or analyzed in this study. Data sharing is not applicable to this article.


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