Volume 22, Issue 3 (May 1994)
Uniaxial Tensile Strength of Cementitious Composites
A brief review of various methods of measuring the uniaxial tensile strength of cementitious composites is presented. The pros and cons of these methods are described. Common problems associated with the traditional uniaxial tension testing techniques exist, and these problems arise from two areas: (1) stress concentration at gripping and (2) misalignment. These testing artifacts can significantly influence the test results, producing measurements that underestimate the intrinsic strength of the material. A novel approach for testing cementitious composites in tension is described. The test uses cylindrical bar specimens 9.5 mm in diameter and 120 mm in length. The specimens are fractured in a hydraulic chamber which allows specimen self-alignment. The advantages of using the technique are minimization of misalignment and stress concentration, larger specimen volume under stress, and determination of initiation of fracture.
The tensile strength values obtained using the hydraulic tension test technique are compared to those obtained by the traditional uniaxial tension tests. The average tensile strength of bigger size specimens, such as 16 mm in diameter and 120 mm in length, was predicted using the application of Weibull theory. Furthermore, these specimens were also tested using the hydraulic tension testing technique. The data show that the predicted values obtained using the application of Weibull theory compare well with the experimental values obtained by the novel teasion testing technique.