CHEMICAL ACTIVATION OF BLENDED CEMENTS MADE WITH LIME AND NATURAL POZZOLANS

This paper deals with the chemical activation of lime-pozzolan cement (LPC), which consists of 80% natural pozzolan and 20% hydrated lime (b y mass). Results show that the addition of 4% Na2SO4 can significantly improve the early strength of this cement. The presence of 4% flake c alcium chloride (CaCl2.2H2O) is not helpful to early strength, but can increase the later strength substantially. CaSO4.0.5H2O and NaCl do n ot demonstrate an obvious effect on the strength development of the ce ment. Combination of activators, such as CaCl2.2H2O + Na2SO4 or Na2SO4 + NaCl does not improve the activation effect; pastes with 2% Na2SO4 + 2% NaCl show lower strength than the pastes with 2% Na2SO4 alone.