Study lime-based mortars with added silica fume and bioproducts for restoration and preservation of heritage buildings

Abstract

Abstract Restoration of heritage buildings requires an appropriate choice of materials, as inappropriate materials can lead to degradation rather than preservation. Hydrated lime and sand mortars are the most suitable for masonry cladding. However, they have low durability regarding current requirements. This work investigates the use of silica fume and/or biopolymers (egg albumen and additive derived from the reuse of milk unfit for human consumption (k-casein)) in the production of these mortars. Many mortars were characterized in terms of mechanical properties (compressive and diametric strength, absorption rate) and chemical properties (SEM, Infrared spectrum). The research revealed that the addition of silica fume allows an increase of more than 50% in the mechanical strength of the mortars and, when associated with animal protein, this value may be higher than 60%, especially for biopolymer (k-casein). Finally, the proteins in the preparation of mortars, which provides intense air entry, resulting in the formation of more pores. This increase in voids allows more CO2 to enter, which directly contributes to a faster carbonation process and performance mortar.