Title: Suitability of Alkali Activated GGBS/Fly Ash Concrete for Chloride Environments

Author(s): Dali Bondar, Sreejith V. Nanukuttan, Marios N. Soutsos, P.A. Muhammed Basheer and John L. Provis

Publication: Symposium Paper

Volume: 320

Issue:

Appears on pages(s): 35.1-35.14

Keywords: alkali activated slag/fly ash concretes, bulk resistivity, chloride migration coefficient, compressive strength, workability

DOI: 10.14359/51701073

Date: 8/1/2017

Abstract:
This study investigates chloride ingress into alkali-activated slag/fly ash (AA-S/F) concretes with various ratios of slag to fly ash (80/20, 60/40, 40/60 and 20/80). Alkaline activators were a mixture of sodium hydroxide and sodium silicate to obtain between 6-8% sodium hydroxide (NaOH) concentration by weight of cementitious material. The SiO2/Na2O ratios (silica modulus, Ms) of mixtures were 0.45, 1.0 and 1.25. Tests applied included typical fresh and hardened properties, air content, slump, compressive strength, bulk resistivity and non-steady state chloride migration. The results show that while attractive engineering properties can be achieved, the chloride ingress in the AA-S/F concretes studied here with ≥ 20% fly ash is moderate to high and this may make them unsuitable for use in reinforced concrete in chloride environments.