( f e )
Another useful test for fracture of concrete is the wedge-splitting test (Fig. 6.6). It is similar to the compact tension test used for metals. Wedge splitting tests were studied for concrete by Hillemier and Hilsdorf (1977) and the present shape of the test specimen, characterized by a starter notch and a guiding groove which can be either moulded or sawn, was proposed by Linsbauer and Tschegg (1986). The test was subsequently refined by Bruhwiler (1988), and Bruhwiler and Wittmann (1989) who conducted (at the Swiss Federal Institute of Technology) over 300 such tests on normal concrete, dam concrete and other cementitious materials. Very large wedge splitting specimens, of sizes up to 1.5 m (5 ft.), have recently been tested by Saouma, Broz, Bruhwiler and Boggs (1989) at the University of Colorado, to study the size effect in dam concrete.