Prediction of weathering by thermal degradation of a coarse-grained marble using ultrasonic pulse velocity

Engineering properties of building stones can vary because of degradation by weathering agents. Thermal fluctuation is one of the most important agents on deteriorations such as sugaring, bowing, cracking and spalling of marble. As a result, physical and mechanical properties of marble used in the construction of old and/or modern structures are adversely affected by time. On the other hand, some properties of building stones are always required for decision of rehabilitation works. Several kinds of conventional tests have been suggested for characterization of stones, to measure their properties or to evaluate conservation or repair works. However, in most cases, sampling from historical buildings is not possible. Therefore, nondestructive testing methods are often suggested for the prediction of weathering grade of building stones. One of the most practical methods for similar purposes is ultrasonic pulse velocity measurement, which can be performed easily. The main goal of this study is attainment of sound empirical correlations between the ultrasonic pulse velocity and engineering properties of previously deteriorated marble. Experimental works were conducted on seven different specimen categories of a coarse-grained marble having different micro-crack frequencies induced by both cyclical heating–cooling and freeze–thaw actions. The experimental results indicated that physical and mechanical properties of Muğla marble can be reliably estimated for different environmental cases by ultrasonic pulse velocities. P-wave velocities in dry and saturated cases are two sound indicators of both the apparent porosity and the coefficient of capillary absorption, and whereby the sugaring type of deterioration for coarse-grained marbles.