Effect of limestone powder and fly ash on magnesium sulfate resistance of mortar

Abstract

The effect of limestone powder and fly ash on magnesium sulfate resistance of mortar was studied by testing on the strength, expansion and hydration products of the specimens stored in MgSO₄ solution at certain periods. The experimental results show that the strength of mortar stored in MgSO₄ solution increases a little before 28 d, but decreases fast subsequently. The more the contents of limestone powder and fly ash, the less the strength losses. Mortar swells in the MgSO₄ solution with the soaking time. And the more the contents of limestone powder and fly ash, the less the expansion rate is. The expansion or strength loss of mortars results from the expansion of gypsum, as well as the loss of Ca(OH)₂ and other hydration products of cement. The magnesium sulfate resistance of the mortars containing limestone powder and fly ash is high.

Keywords

limestone powder / fly ash / mortar / magnesium sulfate resistance

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