Optimal propotions of wedge splitting test specimen for testing of various cement based composites

různé

angličtina

Classical fracture tests (bending, tensile) as well as the wedge splitting test (WST) can be employed for the determination of the fracture-mechanical parameters of quasi-brittle cement-based building materials. In this paper, the focus of attention is the WST. The influence of the material brittleness (defined by the characteristic length of the material) is numerically investigated in the paper, as is the influence of the relative notch depth on the results obtained from the WST. The aim of the study is to minimize the negative effects occurring during experimental activities, particularly the material damage (and therefore also energy dissipation) taking place outside the desired portion of the specimen – the ligament – especially around the groove corner(s). The analysis has been conducted using cohesive crack modelling tools and, in contrast, linear elastic fracture mechanics and the fracture mechanics of generalized stress concentrators. Two FEM systems have been used for numerical prediction of the fracture behaviour and fracture mechanics parameters: ATENA (the former mentioned approach – cohesive crack modelling) and ANSYS (the latter approach). The results from the used theories are compared and discussed. The results of the WST for the studied materials, which differ in characteristic lengths, are compared and the optimal relative crack/notch length is recommended.

wedge-splitting test, cementitious composites, quasi-brittle fracture, characteristic length, general singular stress concentrator, specimen proportions

ŘOUTIL, L.; VESELÝ, V.; SEITL, S.; KLUSÁK, J.

14. 11. 2011

Luxor, Egypt

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