High-volume fly ash concrete with and without hydrated lime: Chloride diffusion coefficient from accelerated test

Abstract

Fly ash changes the microstructure of paste and can increase concrete durability. Calcium hydrated lime was added to concrete with 50% of the cement, by weight, substituted with fly ash, with the intent of replacing some of the calcium hydroxide consumed by the pozzolanic activity. Three proportions of mixes were studied: concrete with high early strength cement (HESC), concrete with 50% HESC and 50% fly ash, and concrete with 50% HESC, 50% fly ash and an additional 20% of hydrated lime. They were then tested according to ASTM C1202, but with the application of a voltage of 30 V during 35 h. Results revealed that concretes containing fly ash and hydrated lime presented a lower accumulated charge density and coefficient of chloride diffusion than the HESC concrete used as a reference.