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
5.4.3.1 Apparatus
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.
No comments:
Post a Comment