Title: Influence of Fly Ash on the Sulfate Resistance of Concrete

Author(s): P. J. Tikalsky and r. L. Carrasquillo

Publication: Materials Journal

Volume: 89

Issue: 1

Appears on pages(s): 69-75

Keywords: concrete durability; ettringite; mineral admixtures; gypsum; fly ash; mix proportioning; portland cements; pozzolans; sulfate attack; sulfate resistance; x-ray diffraction; Materials Research

DOI: 10.14359/1247

Date: 1/1/1993

Abstract:
The sulfate resistance of concrete containing fly ash was investigated in a laboratory study in which concrete specimens were continuously soaked in a 10 percent sodium sulfate solution for 18 months. Eighteen fly ashes and two other pozzolans were used as a partial replacement for Type II portland cement in a standard 4000-psi mixture design. The chemical and mineralogical composition of each pozzolan was determined according to ASTM C 311 and X-ray diffraction techniques. In addition to the effects of fly ash composition on the sulfate resistance of concrete, the study investigated the effects of the level of fly ash replacement, slump, air content, cement type, and moist-curing time. Results of this research program showed that compositional effects of fly ash dominate over physical effects of fly ash on the sulfate resistance of the concrete.