Evaluation of Pozzolanic activity and lime reactivity of fly ash, GGBS, mica powder and pumice as binders

Abstract

This article presents the effect of the pozzolanic activity and lime reactivity of various siliceous materials, like fly ash, GGBS (Ground granulated blast furnace slag), mica and pumice powders. The pozzolanic activity is evaluated as per ASTM and lime reactivity test as per IS 1727. Based on the ASTM C311 tests, at 28 days GGBS, pumice and fly ash showed 71%,12% and 9% improvement in strength respectively in comparison with the control mix for 20% replacement of binder. Mica powder showed decrease of strength in comparison with the control mix. It has been observed that all binders satisfy the criteria of requirement of strength as per ASTM C311 activity index which is greater than 0.75. Based on the lime reactivity tests carried out as per IS 1727 carried out, maximum lime reactivity has been observed in case of GGBS (26%), followed by fly ash (25%), pumice (9%) and mica powder (8%) in comparison with the control mix with 20% replacement of hydrated lime.