Sustainable Waste-Based Materials for Conservation of Built Environment

Waste-based binders/mortars were synthesized, characterized and their suitability for restorative applications was assessed. The waste-based organic and ceramic additives either in alkali-activated materials or new lime mortars demonstrated high potentials as precursor/addition in restorative materials. As the first phase of the dissertation, binders from alkali-activation of brick waste powder were synthesized, characterized and evaluated as possible materials for repointing historic/old masonries. The binders in two different curing temperatures (room temperature and 50 °C) with nominated SiO2/Al2O3 molar ratio ranging from 1.4 to 0.4 were investigated. Pastes with intermediate nominal molar ratio exhibited open porosity and water vapor permeability falling in the index range of historic lime-based mortars, thus demonstrating to be potentially compatible with them. As the second phase of the dissertation, suitability of new lime mortars for restorative rendering applications was investigated. Three categories of air-, formulated- and hydraulic-lime mortars were synthesized with inclusion of two different types of spent sunflower cooking oils; when necessary, brick waste dust was added as pozzolanic addition. The results of spent oils addition in the mortars exhibited promising hydrophobic effects. The effect of unsaturation level of additive oils on hydrophobicity of the mortars was discussed. In the third phase of the dissertation, air- and formulated lime mortars with pulverized brick waste were synthesized with addition of two organic waste-based additives: spent cooking oil and albumen. Parallel valorization of albumen as organic protein source and fatty acid additive demonstrated enhanced setting time and improved hydrophobicity and enhanced durability at the same time, for both mortar categories. Parallel valorization of organic additions in lime mortars can explore high potentials in designing restorative materials with low environmental impact and high respect to the feature of historic mortars.