The reaction between aggregate and cement paste in autoclaved concrete

This study was made on the reaction between aggregate and cement paste in autoclaved concrete and its influence on compressive strength. The specimens mixed with cement and various crushed minerals (149–74 μm) were autoclaved at 181°C for 1–168 hours. Quartz and feldspars (microcline, albite and anorthite) reacted to cement paste, whereas hornblende, augite and olivine did not react. The reaction rate of minerals were, in order, anorthite > quartz > microcline=albite. 11A tobermorite was formed by the reaction between cement paste and quartz, and feldspars. Hydrogarnet was also formed by the reaction between cement paste and anorthite. The compressive strength of the specimens containing quartz and feldspars increased as the curing time was prolonged.