a new apparatus for measurment of anisotropic tensile strength of rock

The experimental tests used to investigate the anisotropic tensile strength of the rock like material (concrete) using compressive to tensile load convertor (ctlc) device. for this purpose, the concrete slab containing a central hole was prepared, and situated in the ctlc device which in turn placed in the universal testing machine. the cubic slab has the dimensions 19cm*15cm*15cm with a central hole of 7.5 cm in diameter. the rate of the applied compressive load to ctlc device through the universal testing machine was 0.02 mpa/s. samples have three different configurations related to loading axis; 0, 45°, -45°. the direct tensile strength of the slab is measured due to the direct tensile stress which is applied to this specimen by the ctlc device. this novel device transferring the applied compressive load to that of the tensile during the testing process. concurrent with indirect tensile test, brazilian test was also performed to compare the results from the two methods. results obtained by this device were quite encouraging and show that the tensile strengths of concrete were similar in different directions because of the homogeneity of bonding between the concrete materials. also, the direct tensile strength was clearly lower than the brazilian test strength test.