open access

https://hdl.handle.net/2115/97965

Reaction and microstructure of metakaolin-based geopolymer

英語

pore structure

2025-11-02

Taylor & Francis

Journal of Sustainable Cement-based Materials

14(11)

2335-2348

The reaction mechanism of geopolymers remains unclear, yet it significantly influences their early-age properties such as strength and microstructure. In this study, the heat of reaction and compressive strength were measured for geopolymers with varying SiO2/Al2O3 and H2O/Al2O3 ratios. Results showed that increasing both ratios decreased the degree of reaction and the peak heat flow, likely due to reduced alkalinity and hindered dehydration during polymerization. A certain degree of reaction is essential for strength development, while unreacted metakaolin can act as a filler, contributing positively to strength. An increased H2O/Al2O3 ratio initially enhances workability and strength, but excessive water leads to higher porosity and reduced strength. Based on the balance between reactivity and porosity, the optimal mix proportions were found to be SiO2/Al2O3 = 3.5-3.75 and H2O/Al2O3 = 11 for K-based geopolymers, and SiO2/Al2O3 = 3.75 with H2O/Al2O3 = 11-12 for Na-based geopolymers.

学術雑誌論文

Accepted Manuscript

This is an Accepted Manuscript of an article published by Taylor & Francis in Journal of Sustainable Cement-based Materials on 2 Nov 2025, available at: https://doi.org/10.1080/21650373.2025.2531266.

2165-0373