Role of lightweight fillers on the properties of a mixed-binder mortar

This work presents a study on the effects of lightweight natural fillers, such as vermiculite and perlite, on the properties of a mixed-binder mortar based on a cement/lime/sand formulation with a typical ratio of 1:1:6. This kind of mortar may be used for indoor and outdoor rehabilitation purposes. Mortars with different contents of the above-mentioned fillers were prepared and their effect on the fresh and hardened product characteristics was evaluated. In the fresh state condition, properties such as apparent density, air content and water retention ability were measured. In what concerns the hardened product characteristics, evaluation was based on the variations of mechanical properties, open porosity and capillarity. It is observed that both the content and the nature of the lightweight filler determine the final characteristics of the mortar. This is particularly enhanced, for instance, by the relationship between hardened product physical properties, microstructure and porosity distribution.