Evaluating the Resistance of Activated Natural Pozzolan Against Cycles of Freeze-Thaw and Salt-Frost Attack

Present research evaluates the resistance of natural pozzolan activated with a solid-compound activator against cycles of freeze-thaw. The deteriorating effects of the freeze-thaw cycles were evaluated through measuring the compressive strength, the total open pore volume, and the amount of water absorption of the mortar specimens. Activated natural pozzolan shows 100% loss of compressive strength after just 75 cycles of freeze-thaw, whereas Portland cement resists 200 cycles of freeze-thaw with only 17.4% reduction in compressive strength. The results obtained for the total open pore volume and the amount of water absorption also confirm the higher vulnerability of the activated natural pozzolan compared to Portland cement. After 50 cycles of freeze-thaw in the presence of 1.5, 3 and 4.5% calcium chloride solution, the mount of scaling in the mortar prisms of activated pozzolan is almost 4 times higher than that of mortar prisms of Portland cement.