Core Test
The points from which the cores to be taken can be established from cube testing register. If not possible it can be at the descretion of inspecting authority. The number of test cores will be not less than three which should represent the whole of the doubtful concrete.

The core strength should be converted to equivalent cube strength. If the equivalent cube strength gives at least 85 per cent of characteristic strength of the grade of concrete, and no individual core has a strength less than 75 per cent, the strength of the concrete can be considered adequate.

In case the core test results do not satisfy the requirements or where such core tests have not been done, load test may be resorted to.

Load Tests for Flexural Member
The structure should be subjected to a load equal to full load plus 1.25 times the live load for a period of 24 hours and then the imposed load is removed.

The deflection due to imposed load only is recorded. If within 24 hours of removal of the imposed load, the structure does not recover at least 75 per cent of the deflection under super imposed load, the test may be repeated after a lapse of 72 hours. If the recovery is less than 80 percent, the structure is deemed to be unacceptable.

If the maximum deflection in mm, shown during 24 hour under load is less than 40 L2 / d, where l is the effective span in metre and D, is the overall depth of the section in mm, it is not necessary for the recovery to be measured and the recovery provision mentioned above does not apply.