Effect of sugarcane biomass waste in cement slurries submitted to high temperature and pressure

Cementitious materials are subjected to changes in their microstructure and mechanical behavior when submitted to high service temperatures. In the oil industry, Portland-based slurries are used where conditions imply high temperatures and high pressures, e.g., steam injection or recovery of heavy oils. The present study investigated the hydration behavior and mechanical strength of cement slurries containing sugarcane biomass waste or silica flour, submitted to high temperature and pressure cycles using a curing chamber. The slurries were initially cured for 28 days at 22 °C. After that, they were placed in a curing chamber for 3 days at 280 °C and 17.6 MPa. The results showed a decrease in the compressive strength of the slurries submitted to high temperature high pressure. The decrease in strength was less marked in the slurry containing 40% of sugarcane biomass waste, as a consequence of the formation of silica-rich phases, i.e., xonotlite and tobermorite. When the slurries were placed in the curing chamber at 280 °C and 6.9 MPa for 7 days (after initial curing for 14 days at 38 °C), the slurry containing 59% sugarcane biomass waste showed an increase in compressive strength, contrary to what was observed for all the other slurries tested.