In Japan, natural pozzolans are abundantly available due to the widespread distribution of volcanic ash deposits, and have been used in concrete construction for more than 150 years. In recent years, volcanic glass powder (#VGP), produced by grinding and classifying volcanic ash to extract its amorphous fraction, has been standardized as a cementitious material in Japan and is increasingly being applied in practice.

In this study, we conducted comprehensive hydration analyses and physical property evaluations of the OPC–VGP system up to one year of age to clarify the mechanisms of hydration reactions and strength development. High-resolution #SEM observations revealed the morphological evolution of C–S–H formed around VGP particles, providing detailed insights into how the pozzolanic reaction contributes to microstructural development.

Although the pozzolanic behavior of volcanic materials has been widely recognized, this study provides new and essential data specifically relevant to the use of VGP in Japan, offering valuable information for both research and practical applications.

Y. Ren, A. Tomoyose, I. Maruyama, Long-term hydration and pozzolanic reactivity of volcanic glass powder in blended cement systems: Microstructural evolution and compressive strength development, Constr. Build. Mater. 494 (2025) 143331. https://doi.org/10.1016/j.conbuildmat.2025.143331.