Early hydration of calcium aluminate cement blended with spent FCC catalyst at two temperatures

Abstract

The early hydration (up to 24h) of calcium aluminate cement (Al2O3 min. 40%) blended with spent FCC catalyst at two temperatures i.e. 10 ̊C and 25 ̊C was investigated. The calorimetric measurements were used to study cement pastes with constant ratio of water/binder = 0.5 (binder = cement + addition) and containing 0, 5 and 25% mass of mineral waste as replacement part of cement. In addition the kind of created products using X-ray diffraction method was identified. On the basis of obtained results it was found that the influence of spent FCC catalyst on early hydration of calcium aluminate cement strictly depends on temperature of hydration process. At the temperature of 25 ̊C this waste aluminosilicate accelerates setting and hardening of cement, but at the temperature of 10 ̊C acts as retarder. These changes are realized by variation of duration of the induction period and the bigger content of FBCC the bigger the effect is regardless of the temperature of hydration. The presence of this mineral waste causes a minor effect on the crystalline hydrates produced after 1 day of hardening although it clearly increases degree of CA hydration.