Читать книгу Monument Future - Siegfried Siegesmund - Страница 75

Restoration mortar designates a group of products made to repair a damaged masonry. They are used to rebuild the lost parts of buildings, monuments or sculptures that have disappeared and to make replicas of architectonic or sculptural elements of high cultural value, placed inside buildings or museums to ensure their conservation. Mortars for restorations must be carefully selected before application. They have to be able to interact with the ancient stone and match in a chemical, physical and mechanical way with the pre-existing materials (Rota Rossi Doria, 1986; Torney, 2016). The choice of the mortar must take into account the support properties and the environment in which the mortar will be applied. Nowadays, in the development of new commercial restoration mortars, their environmental impact and their durability in future conditions are not always considered.

Our work aims at proposing solutions to produce more ecological and durable mortars. This research will allow the development of a series of new restoration mortars which design will be done in a “circular economy” philosophy.

To develop new sustainable formulas, we tested different additives available in Paris region, with a low CO2 footprint and capable to improve the 60mechanical properties of resulting mortars. Inorganic additives such as crushed bricks, crushed glass and slags have been identified in historical mortars. The use of recycled materials is considered as a zero CO2 emission contribution to the mortar footprint; only the energy used to transform these materials: grinding or cleaning is considered in the total environmental balance. For this reason we included recycled additives in our formulations. Crashed bricks (Aalil et al 2019) and waste glass powder (GWP) have been used in construction works because they improves the durability and the compressive strength of lime mortars (Carsana et al. 2014). GWP provides a pozzolanic behaviour to lime mortar (Edwards et al. 2007).

Many studies have been done about the influence of kind of binder, composition and particle size of aggregates on the physical and chemical properties of mortars. For example, the use of limestone sand as aggregate is recommended to ensure a better compatibility with natural stones (Szemerey-Kiss et al. 2011).

In ancient cultures like Mayans and Romans, organic additives were used to improve the properties of the mortars (Villaseñor et al. 2009; Ordóñez et al. 2019). For example, the tannin and sugar content of the pinecones ensured water resistance and plasticity of mortars (Rampazzi et al 2016, Arcolao 1998). In restoration, it is very important to dispose of mortars with different ranges of physical and mechanical properties using natural additives and without using any cement. (Russlan et al. 2018).