The role of aggregate characteristics on the performance optimization of high hydraulicity restoration mortars

Performance characteristics of mortars are governed by the type of binder, type and grain size distribution of aggregates and their mix proportions. Aiming at parametric optimization of NHL restoration mortars, this study discusses the effect of physical and geometrical properties of aggregates on fresh and hardened mortars, tested after 28 days of curing. Four different sands 0/2 mm were studied and ten mixtures were prepared with natural hydraulic lime (NHL5). The effect of gradation, packing density and shape of aggregates was studied, versus the mechanical properties and porosity. The results highlight the crucial role of the morphological parameters of aggregates, especially of packing density, on the development of microstructure and the mechanical performance of mortars. The contribution of aggregates to tailoring and controlling the mechanical and microstructural properties of repair mortars is also demonstrated in this work. To this end, it was proved that the mechanical performance of mortars is controlled by the combination of both binder amount and packing density of the aggregates.