High-Temperature Processing and Applications of Silica-Modified Portland Cement CBC Composites

Silica-modified portland cement-based Chemically Bonded Composites (CBCs) have been prepared and cured to elevated temperatures. It has been found that when cementitious composites with calcium-to-silica (C/S) ratios of 0.83 are thoroughly hydrated through hydrothermal curing, followed by careful dehydration, mortars of exceptional strength are produced. The bulk of this strength is maintained to over 600°C. X-ray diffraction studies of binder samples dried at 200°C and 500°C show only slight differences in mineral product contents. Above 600°C, a drop in strength is noted, and a substantial portion of the binder converts to wollastonite. Even so, these CBC composites retain as much as 40% of their peak compressive strength to temperatures up to 800°C. Applications of these materials in high-temperature industrial processes are presented.