Correlation models for utilising rebound hammer technique in evaluating weathered limestone walls

ABSTRACT Rebound hammer (RH) is a non-destructive testing (NDT) technique that has a significant role in the field assessment of ancient and modern buildings made of natural stones. This study aims to establish correlation models for utilising the RH technique in evaluating weathered limestone walls and to provide an efficient in-situ assessment. Compressive and RH tests were conducted for four types of building limestones: Ruwaished Hard, Ruwaished Soft, Hallabat, and Ma’an, including nine specimens for each type with dimensions of 15 × 15 × 15 cm and two real-scale weathered stone walls with dimensions of 100 × 200 cm. Based on the experimental tests, regression analyses were conducted between the RH values, compressive strength, and modulus of elasticity. The established power-based correlation models had high coefficients of determination. For validation purposes, real-scale weathered stone walls were evaluated using the RH test, the mechanical properties were underestimated and affected by Stone Units’ surface roughness and weathering degrees. However, the established models give conservative estimations and can be used with sufficient accuracy for an in-situ evaluation of limestone structures. Further investigations are necessary to enhance models’ validity for various stone types by combining other NDTs and considering different weathering factors.