The pozzolanic reactivities of some New South Wales flyashes and their application to soil stabilization

Abstract

The reactivities of a number of flyash samples from various electric power stations in New South Wales and their potential value as pozzolanic materials have been investigated. The hydrated calcium aluminates and silicates crystallizing as products of the lime flyash interaction were identified in pastes cured at 35 degrees to 40 degrees centigrade and in compacted mixtures aged under ordinary conditions. The effects of pretreating the flyash with acid or alkali washes, as well as the influence of unburnt carbonaceous material on the formation of the crystalline reaction products have also been determined. The nature of the reaction products formed in lime flyash clay mixtures was investigated in pastes as well as in compacted samples. The conclusions reached were used as a basis for the interpretation of the changes induced in clays by lime flyash additions. Recommendations have been made on the soil types and materials most suitable for lime flyash stabilization (A).