Comparative study of chloride ion migration in cement and epoxy matrix mortars: influence of recycled sand

Abstract

This study aims to evaluate the possibility of using recycled sandto develop sustainable mortars against the diffusion of chlorideions. Comparative studies were carried out on cement-basedmortars (CM) and epoxy (called resin mortar and designated RM)manufactured with a standardized sand and another recycledcoming from the demolition of buildings. The effect of theincorporation of a thinner, methyl octanoate, on the workability,mechanical properties and durability of epoxy mortars wasexamined. Results show that the RM mortars have a workabilitythat improves with increasing the percentage of epoxy content andwith the addition of the thinner. The total substitution ofstandardized sand with recycled sand alters this property. Theresin mortars have a lower porosity than the cement basedmortars, better mechanical properties and better resistance to themigration of chloride regardless the nature of sand. Thesubstitution od natural sand by recycled one does not significantlyaffect the mechanical properties of resin mortars with identicalpercentage of binder (20%). However, it causes a slight decreasein the resistance to the migration of chloride ions attributed to atotal porosity accessible to fluid higher for the MR formulatedwith recycled sand. Similarly, the migration of chloride ions intomortar decreases with increasing the resin percentage, a decreasejustified by the reduction of the total porosity. The incorporationof a thinner into the polymeric binder affects the mechanicalproperties but does not alter the resistance of the MR to chlorideions migration which remains significantly higher than that ofCM. The use of recycled sand decreases this resistance.