Salts are a common substance found on buildings, which can cause an efflorescence effect This phenomenon can impact not only the aesthetics of the walls, but also the internal structure of the materials, triggering serious damage and eventual failure To have a better understanding of the salt crystallization in lime mortars, six lime cement mortar mixtures were made to study their durability after being contaminated with a 5% NaCl solution using different ageing regimes 3 D micro computed tomography models were obtained before and after artificial weathering to analyze and compare their 3 D micro structures and the resulting salt crystallization in a non-destructive way.