The Evaluation of Non-Destructive Tests for the Strength and Physical Properties of Granite, Marble, and Sandstone: A Case Study from North Pakistan

Abstract

Nondestructive tests, commonly employed in rock mechanics, estimate mechanical parameters without affecting the rocks in situ properties. This study evaluates non-destructive tests (ultrasonic pulse velocity and Schmidt hammer) for forecasting the strength and physical properties of commonly used rocks. Weathering grades and moisture content are provided as variables that produce variances in both non-destructive tests. The coefficient of determination (R²) and subsequent empirical equations for the best-fit trend line are calculated using a simple regression method. The ultrasonic pulse velocity is found to be more efficient in estimating most of the physical properties (specific gravity, porosity, water absorption, and dry density) of granite, marble, and sandstone, with high correlation coefficients. Whereas the Schmidt hammer is found to be more reproducible in determining the strength (compressive and tensile) of granite, marble, and sandstone. The student’s t-test proved the sensitivity and correctness of the acquired equations from the suggested correlations, and agreement was established between measured and estimated plots of strength and physical properties. Although the student’s t-test confirms that the performance of all empirical models established in this study are significant, any non-destructive test with a low R² value should be used with caution when estimating the studied properties.