Sulfate corrosion of portland cement-pure and blended with 30% of fly ash

Abstract

This paper considers the sulfate corrosion of Portland cement-pure and blended with 30 wt% of fly ash. As raw materials, three kinds of Portland cements, with different content of C 3 A (5.45-11.84 wt%), were applied. Fly ash was added so as to decrease the C 3 A content (to 3.82-8.29 wt%). The test samples were exposed to the influence of aggressive environment (solutions with 1000 and 2000 mg/l of the SO 4-2 ions as well as 320 mg/l of the NH 4-2 ions). Experiments lasted six months, while the flexural strengths were measured after 1,2,4 and 6 months. The corrosion resistance factor was calculated. For the examined systems, a correlation was suggested. It expresses the resistance factor as a function of three independent variables (the C 3 A content, duration of corrosion process and concentration of the SO 4-2 ions).