Measurement of durability properties of unitary and binary mortars containing supplementary cementitious materials
- Vol.97(6), Jun
- Thane ACC LTD 2023
- 46-54p.
Sulfate attack is a deteriorating phenomenon in concrete and is responsible for strength reduction, development of cracks, and disintegration of concrete and volume expansion. Use of supplementary cementitious materials (SCM) has been effective in improving the sulphate resistance and is dependent on the characteristics of SCM used in concrete. In the present investigation low-carbon metakaolin (MK) has been employed as a supplemented cementitious material to prepare cement mortars. Sulfate attack testing in sodium and magnesium sulfate solutions has been performed. The usual test method has been used to determine the sulfate resistance of these combinations to expansion and loss of compressive strength. In mortars, the water-cementitious content (w/cm) ratio and Metakaolin dose has ranged from 0.45 - 0.55 and 0 - 10 % (by mass), respectively. Mortars with w/cm = 0.45 displayed negligible degradation, signifying that they are sulfate resistant. The control mortars showed higher degradation than the Metakaolin mortars having w/cm = 0.50 to 0.55. The sulfate resistance of mortars reduced with increase in Metakaolin dose at any given w/cm ratio. While both sodium and magnesium sulfate degraded the specimens, the former resulted in enhanced expansion of the specimens studied, whilst the latter resulted in considerable compression strength loss. Metakaolin mortars had a sulfate resistance that was comparable to that of silica fume mortars.