Title: Carbonation and Chloride-Induced Corrosion of Reinforcement in Fly Ash Concrete

Author(s): M. N. Haque and M. Kawamura

Publication: Materials Journal

Volume: 89

Issue: 1

Appears on pages(s): 41-48

Keywords: calcium chlorides; carbonation; compressive strength; concretes; corrosion; fly ash; fresh concretes; half-cell potential; Materials Research

DOI: 10.14359/1243

Date: 1/1/1993

Abstract:
Two grades of concretes with and without fly ash and with and without CaCl 2, with total cementitious contents of 250 and 350 kg/ 3, were designed. The concretes were cast with 0, 0.5, and 2 percent of Cl - by weight of cementitious materials. The compressive strength development, extent of carbonation, and the half-cell potential of steel bars in the various concrete specimens exposed to the outdoors were monitored for a period of up to 4 years. The results of this investigation indicate that concretes with 30 percent replacement of cement by fly ash, on equal weight basis, carbonated more than the control concretes. The 4-year strength of the fly ash concretes, however, was 18 percent less than the plain concretes. The results also suggest that the half-cell potential referenced to CSE is not a reliable indicator of the extent of corrosion. The extensive cracking in all the reinforced fly ash concrete specimens with 2 percent Cl - of the total cementitious content establishes the comparatively higher corrosion susceptibility of concretes made with fly ash.