Commercial NHL-containing mortars for the preservation of historical architecture. Part 1: Compositional and mechanical characterisation.

This paper presents the characterisation of a selection of NHL-based commercial products for the conservation of historic masonries. Two binders and four ready-mixed mortars have been analysed; both the anhydrous raw materials and the hardened mortars have been studied, focusing on those parameters which can be used as selection criteria. The influence of different curing conditions on the final microstructure has been considered as well, in order to simulate the real application. Despite the similar commercial indications provided by the manufacturers, the results show remarkable differences for what concerning both the initial composition and the final behaviour of the mortars.