The optimal design of double-edge wedge-splitting tensile test for ultra high performance concrete

Abstract

The double-edge wedge-splitting (DEWS) test is a new indirectly tensile test, those of stress distribution similar with the uniaxial tension state. However, there are no standard rules regarding the splitting specimen and groove dimensions suitable for the UHPC tensile properties. In this paper, DEWS test, conventional splitting test, and direct tensile test were performed to measure the tensile strength and tensile stress vs. crack opening response of UHPC. The digital image correlation (DIC) technique was utilized to detect the crack propagation paths and fracture modes. Two specimen shapes, three groove angles and three fiber types are utilized to this investigation. The experimental results of 18 DEWSs under tensile loading, including peak strength, tensile stress-COD curves, fracture modes and properties, and the crack paths, are presented. The results show that the UHPC tensile performance used with cubic specimen is less sensitive to groove angle than in the cylinder. An important finding is that DEWS test used with 45° grooved cube specimen presents the lowest variation in peak strength and stress-COD curve for UHPC tensile behaviors. After comparison, the tensile strengths using DEWS test and direct tension test are essential equal in first-cracking and peak strength. The crack paths and fracture mode are basically the same inside the DEWS and direct tension specimens. Accordingly, the DEWS test used with 45° grooved cubic specimen is suggested for measuring the UHPC tensile property.