Proposing New Equations Using Friction Transfer Novel Method to Estimate the Compressive Strength of Different Stones and mortars

Most of the methods for estimating the strength are either destructive or have expensive and imported equipment. Some of them also indirectly measure the strength. Therefore, a test that has cheap, simple and available equipment, with high accuracy, can be applied in all conditions, has minor damage and can be performed both in the laboratory and on the project site, it is required. Therefore, in this article, the compressive and tensile strength of different mortars and stones have been measured using a in-situ method with cheap and available equipment called "friction transfer" test. In this test, first a partial core with a diameter of 50 mm is created on the surface of the sample, and then the friction transfer device is fixed on the core and using a normal torque meter, a torsional anchor is applied to the core until it fails. be made Then, by determining the surface resistance obtained from the friction transfer test and comparing the obtained results with standard tests, the equations obtained to convert the results from the "friction transfer" test into the uniaxial compressive strength of the materials are presented. Tests were performed on seven different types of stone and cement mortars that are used in normal repair works. The obtained results show the high accuracy of the friction transfer test in measuring the strength of stones and mortars. The coefficient of determination between the results of the friction transfer test and the uniaxial compressive strength of the stones was found to be 93.2%, and according to the calibration curve, by using the friction transfer test, the compressive strength of the stones can be determined using the equation y=1.67x+90.8 measured. Also, by using the friction transfer test, the compressive and tensile strength of mortars can be measured with an accuracy of about 94%.