A Novel Method for the Determination of Direct Tensile Strength of Brittle Materials Using Expansive Cement

A novel method for determining the Direct Tensile Strength (DTS) of brittle materials such as rock and concrete is proposed in this study. Using an instrumented thick-walled cylindrical specimen filled with Expansive Cement (EC), the tangential (tensile) strain induced in the specimen as a result of the expansive pressure exerted on the inner wall of the cylinder is captured. Lame’s thick-walled cylinder formulations for pressure and tangential (tensile) stress are adopted for determining the tensile strength of the material using the recorded tensile strain at failure. Finite element (FE) modeling is carried out to ascertain the location of uniaxial tensile strain along the outer surface of the cylindrical specimen to satisfy the primary condition of DTS measurements. The Extended Finite Element Method (XFEM) is then used to simulate and predict the fracturing pattern of the thick-walled cylindrical specimen. To ascertain the practicality of the proposed testing method, conventional tensile strength testing methods are also conducted for comparison and validation. To do so, a low-tensile strength marble is considered in this study. It is found that the results obtained from the newly proposed testing method are in good agreement with the conventional testing methods including the Glued Ends Direct Tensile Strength (GEDTS) test and the Brazilian Tensile Strength (BTS) test. A suitable specimen configuration is proposed for testing the thick-walled cylindrical specimen with the new method.