Pozzolanic properties of a geothermal silica waste material

The pozzolanic reactivity of a silica waste from a geothermal power generat ing plant in Mexico has been assessed. Pastes of portland cement with 25% s ubstitution of the silica waste were hydrated at 10, 30, and 50 degrees C. The concentration of CH and nonevaporable water were estimated by thermogra vimetry. The silica waste displayed a pozzolanic behaviour from the early d ays of hydration that was favoured by the increased hydration temperature. The nonevaporable water percentages of the blended cement were superior to those of the neat cement, which suggested an enhancement of the cement hydr ation. (C) 1999 Elsevier Science Ltd. All rights reserved.