Corrosion resistance of alkali-activated slag cement

This paper examines the corrosion of alkali-activated blast furnace slag cement in pH 3 nitric acid, pH 3 acetic acid, 30% CaCl₂ solution and 15% CO₂ atmosphere at relative humidity of 52%. ASTM Type I Portland cement is used as a reference. Experimental results indicate that alkali-activated slag pastes are corroded more slowly than Portland cement pastes in these acid and salt solutions. Alkali-activated slag pastes are carbonated very quickly during an accelerated carbonation test because of shrinkage cracking, while no carbonation can be detected on Portland cement pastes after 75 days of exposure to 15% CO₂ at a relative humidity of 52%. Detailed analyses indicate that all these differences can be attributed to the difference in hydration products in the two types of hardened cement pastes.