Salt crystallization is one of the most destructive degradation mechanisms in porous building materials, but the performance of lime mortars under such loads has not yet been sufficiently investigated. This dissertation examines the microstructural behavior and durability of lime mortars exposed to sodium chloride and sodium sulfate, focusing on compositional variations due to additives and recycled materials.
Using complementary analytical methods, the research demonstrated that partially replacing lime with cement increases strength but reduces porosity and breathability, leading to greater susceptibility to salt damage. Various evaluation methods were compared to assess their suitability for studying lime mortars. A modified RILEM protocol proved to reproduce the damage patterns in lime mortars more realistically.
Mixed functional additives based on phosphonate and polyacrylate improved strength and carbonation and altered the dynamics of salt crystallization, reducing damage at higher dosages. Recycled aggregates, zinc oxide, and bacterial additives yielded mixed results, highlighting the trade-offs between mechanical strength, durability, and environmental friendliness.
Overall, this work contributes to a better understanding of the mechanisms of salt damage in lime mortars and supports the development of optimized, compatible, and environmentally friendly formulations for both historic preservation and modern construction.