Non-destructive testing for the assessment of granite decay in heritage structures compared to quarry stone

Several types of granite found in two architectural heritage monuments were assessed with two non-destructive, portable techniques: Schmidt hammer rebound and ultrasound velocity (V_p). Similar assessments were conducted on the rock from which the granite was originally quarried for comparison. The results obtained, which revealed the existence of a direct correlation, constitute a useful indication of decay, particularly if the approximate dates of construction are known. And conversely, if they are not, such stone assessments may provide a rough estimate of when the structure was built. Both of these convenient, portable and non-destructive techniques may be used as reliable indicators of the degree of stone decay.