INFLUENCE OF QUARTZ PARTICLE-SIZE ON THE CHEMICAL AND MECHANICAL-PROPERTIES OF AUTOCLAVED AERATED CONCRETE .1. TOBERMORITE FORMATION

The chemical reactions in the hardening of autoclaved aerated concrete (AAC) block were investigated using ground quartz of different partic le sizes. The samples were prepared at 180 degrees C under saturated s team pressure for various times from 0.5 to 64 h. Autoclaving for 0.5 h yielded 1.1-nm tobermorite, suggesting that the utilization of finer quartz has the advantage of reducing the processing time. The tobermo rite formed had higher crystallinity with coarser quartz. The degree o f reaction of finer quartz was higher than that of coarser quartz afte r shorter periods of autoclaving, but lower after longer periods of au toclaving. Gyrolite was formed after 64 h when finer quartz was used.