5.4.2 Cylinder test for tensile strength
The test is carried out by placing a cylindrical specimen horizontally between the loading surfaces of a compression testing machine and the load is applied until failure of the cylinder, along the vertical diameter.
The loading condition produces a high compressive stress immediately below the two generators to which the load is applied. But the larger portion corresponding to depth is subjected to a uniform tensile stress acting horizontally. It is estimated that the compressive stress is acting for about 1/6 depth and remaining 5/6 depth is subjected to tension.
In order to reduce the magnitude of the high compressive stresses near the points of application of the load, narrow packing strips of suitable material such as plywood are placed between the specimen and loading plates of the testing machine.
5.4.3 Beam test for flexural strength
The testing machine shall confirm to the requirements of the sections on basis of verification, correction and time interval. Motorized pumps or hand-operated positive displacement pumps having sufficient volume in one continuous stroke to complete a test without requiring replenishment are permitted and shall be capable of applying loads at a uniform rate without shock or interruption. The third-point loading method shall be used in making flexure tests of concrete employing bearing blocks which will be perpendicular to the face of the specimen and applied without eccentricity.