Micro-Raman study of stable and metastable phases in metakaolin/Ca(OH)2 system cured at 60 °C

►Metastable hexagonal aluminate phases have been identified by Raman spectroscopy. ►Raman spectroscopy determines metastable phase transformation to stable hydrogarnets. ►No C-S-H gel is formed at longer hydration times at 60 °C.