Assessment of limestone cladding deterioration due to crystallisation of salts by non-destructive techniques

Although limestone is widely used in buildings as a cladding material, it suffers accelerated degradation with the passage of time and exposure to environmental agents. Early detection of such pathological processes would allow the adoption of corrective measures and limit the damage to limestone elements. In this study, the effectiveness of three non-destructive techniques-infrared thermography, 3D optical roughness, and acoustic impedance gun measurements-for the early identification of superficial damage generated during the progress of the accelerated ageing test is analysed. The results indicate that although these techniques complement each other, thermography and 3D optical roughness are the most effective for studying deterioration in fine-grained carbonate stones with low porosity, while thermography and acoustic impedance gun techniques provide more valuable information on porous carbonate stones of the calcarenite type.