Ultrasound propagation speed and mass changes by application of different accelerated artificial ageing tests in...

In this work the ultrasound propagation speed on the three spatial planes (Vx,Vy,Vz) and the weight loss/gain of three ornamental granites (Ávila, Spain) were determined before, during, and after being subjected to 90 cycles of three types of accelerated ageing processes (typical of cold regions): a) freezing/thawing and cooling/heating, b) salt crystallisation, and c) freezing/thawing and cooling/heating + salt crystallisation. A three-way mixed multivariate analysis of variance (MANOVA) was used for data analysis. Significant variations in the ultrasonic propagation speed and weight loss/gain of the different granites were observed for the three types of accelerated artificial ageing processes compared to the data obtained from the quarry samples, with the Airón Biotitic Granite (G) variety being the most altered granite and the combined freezing/thawing and cooling/heating + salt crystallisation accelerated artificial ageing test being the most damaging. To determine the durability of the different varieties of granite against the accelerated artificial ageing tests studied, the estimated data of compressive strengh, obtained from the ultrasound propagation speed data, were determined, with the Ávila Grey Granite (C) being the most resistant to the ageing tests studied.