Effect of partial and total replacement of siliceous river sand with limestone crushed sand on the durability of mortars exposed to chemical solutions

This study presents a part of different works carried out on a context of local materials valorization and industrial wastes reuse. The main objective of this investigation is to substitute silica river sand (M'zi river) by crushed limestone sand (residues quarries) in the mortar, so as to valorize the crushed limestone sands that are found (in waste form) in large quantities in the region of Laghouat (Algeria), to protect the environment against this waste and to unlock the local construction projects, especially after the ban on local sand extraction from river for environmental reasons. Indeed, the aim of this work is to study the effect of this replacement on the durability of mortar exposed to different chemical environments. In fact, we have to study the behavior of the obtained mortars into three different environments: in open air, in a solution containing lime and in another one containing hydrochloric acid (HCl). For replacement 0%, 50% and 100%, the results showed that, compared to open air environment, conservation in a lime solution has a positive effect on the durability of mortars. In fact, it furthermore improves their physical and mechanical properties such as the mechanical strength, the dimensional variations, etc. In addition, and compared to silica sand, it has been noted that these properties were much higher in the presence of crushed limestone sand in mortar. Concerning the HCl-solution, it has been recorded a negative effect on the durability of mortars. But, it should be noted that this effect was considerably reduced in the presence of crushed limestone sand in the materials. Finally, with introduction of limestone sand in mortar, the improvements were higher: decrease in the permeability, reduction in the mass and strength losses, reduce in the phenomenon of capillary rise and less attack by acid.