Durability Performance of One-Part Fly Ash-Metakaolin Geopolymers Cured at Ambient Conditions
JOURNAL OF MATERIALS ENGINEERING AND PERFORMANCE, 2026 (SCI-Expanded, Scopus)
- Publication Type: Article / Article
- Publication Date: 2026
- Doi Number: 10.1007/s11665-026-14283-2
- Journal Name: JOURNAL OF MATERIALS ENGINEERING AND PERFORMANCE
- Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Applied Science & Technology Source, Chemical Abstracts Core, Compendex, INSPEC, Engineering Source (EBSCO), Materials Science & Engineering Collection (ProQuest), Technology Collection (ProQuest)
- Keywords: durability, fly ash, geopolymer, metakaolin, one-part
- Kayseri University Affiliated: Yes
Abstract
This study examines the effect of metakaolin (MK) content on the mechanical and durability performance of one-part fly ash (FA)-based geopolymer mortars cured under ambient conditions. Fly ash was partially replaced with MK at ratios of 0-50% by mass, and sodium metasilicate was used as the alkaline activator. All specimens were cured at 20 +/- 1 degrees C and 50 +/- 10% relative humidity for 28 days. The results showed that increasing MK content significantly improved both mechanical and durability performance. The 28-day compressive strength increased from 15.1 MPa for the 0% MK mixture to 60.2 MPa for the mixture containing 50% MK, while flexural strength increased from 4.8 MPa to 9.8 MPa. Water absorption and apparent porosity decreased with increasing MK content, and the initial sorptivity coefficient was reduced by approximately 18% at 50% MK replacement. After 300 freeze-thaw cycles, mixtures with higher MK content exhibited substantially lower weight and strength losses compared to the FA-only mixture. In addition, rapid chloride permeability decreased, and reductions in corrosion-induced mass and bond strength losses were observed. Overall, the findings demonstrate that incorporating metakaolin, particularly at higher replacement levels, effectively improves the mechanical performance and durability of one-part geopolymers cured at ambient conditions.