SBCET/CE/SEM. IV/ CONCRETE TECHONOLOGY LABORATRY (4CE8A)
Object: - To determine the flexural strength of Concrete.
Necessity: - This test comes into play when a road slab with inadequate sub-grade support is
subjected to wheel loads and / or there are volume changes due to temperature / shrinking.
Principle: - Flexural strength, also known as modulus of rupture, bend strength, or fracture
strength, a mechanical parameter for brittle material, is defined as a material's ability to resist
deformation under load. The transverse bending test is most frequently employed, in which a
specimen having either a circular or rectangular cross-section is bent until fracture or yielding
using a three point flexural test technique. The flexural strength represents the highest stress
experienced within the material at its moment of rupture.
Apparatus: - Flexural test machine
Brief Procedure: -
1. Test specimens shall be prepared by moldings concrete to a beam section, curing and
storing in accordance with standard procedure. The section of the beam shall be square
of 100 mm or 150 mm. The overall length of the specimen shall be 4d to 5d. The ratio of
d to the maximum particle size of aggregate shall be not less than three.
2. Circular rollers manufactured out of steel having cross section with diameter 38 mm will
be used for providing support and loading points to the specimens. The length of the
rollers shall be at least 10 mm more than the width of the test specimen. A total of four
rollers shall be used, three out of which shall be capable of rotating along their own axes.
CONCRETE TECHONOLOGY LABORATRY (4CE8A)