EXPERIMENTAL STUDY ON SODIUM SULFATE ATTACK ON MORTAR CONTAINING LIMESTONE POWDER AND FLY ASH AT EARLY AGE

摘要

The effect of limestone powder and fly ash on sodium sulfate attack on mortar atearly age was studied by testing the change of the strength,expansion and hydration productsof the specimens stored in Na2SO4 solution at certain periods. Experimental results show thatstrength of mortar stored in Na2SO4 solution increase a little before 28 d,but decrease fastsubsequently. The more content of limestone powder and fly ash,the less strength lose;Mortar swells in the Na2SO4 solution with the development of soaking time. The morecontent of limestone powder and fly ash,the less expansion rate; the expansion and decreaseof strength of mortars result from expansion of gypsum and the lose of Ca(OH)2 and otherproducts of cement,and the mortars containing limestone powder and fly ash have bettersodium sulfate resistance.