Assessment of lime-cement mortar microstructure and properties by P- and S- ultrasonic waves

Lime-cement mortars are used for repairing building walls, improving thermal and acoustic performance through the modification of their composition and, consequently, their microstructure and properties. In order to evaluate the applicability of ultrasonic (US) waves to better understand the relationships among composition-microstructure-properties, an experimental program using transmission P- and S- waves was carried out. The properties of ten mortars were assessed by US parameters as velocity, moduli and attenuation coefficient. Water to binder ratio, porosity and thermal conductivity showed good correlation to US modulus while S-wave attenuation was linked to sound absorption and the incorporation of fibres. Flexural strength correlated to P-wave attenuation, while a combination of S-wave attenuation and moduli was needed to adjust compressive strength. These correlations can be useful tools for predictive models development, composition optimization and US on-site evaluation.