EFFECTS OF LEACHING ON THE PROPERTIES OF MORTAR

Abstract

Leaching of calcium and other ions from hydrates increases the porosity of cement based materials which has a negative effect on strength and durability. This study investigated the effects of leaching on the properties of mortar. Compressive strength and weight of the mortar and pH of leached water at different leaching periods were evaluated. The mortar specimens were subjected to tank leaching test where samples were exposed to demineralized water for 15, 30 and 90 days. The experimental results demonstrate that after leaching, the alkalinity of leached water increased due to the dissolution of calcium and other ions from mortar samples. Generally, for the first 30 days leaching there was no significant negative effect on the properties of mortar, rather leachant act as a curing medium. Due to the dissolution of hydration products, after 90 days leaching period, weight of the mortar specimen was decreased by 0.75% compared to without leaching sample. On the other hand, after 90 days leaching compressive strength of mortar increased by 72.60% compared to without leaching sample. In addition, after 90 days leaching period, compressive strength and weight decreased by 23.48% and 1.48% respectively compared to 30 days leached specimens.