Non Destructive Tests of Concrete

Non destructive testing of concrete can be defined as the test method used to examine the properties of concrete used in the actual structure. These test methods can also be said as in-situ tests or in-place tests. Traditionally these tests are said to be as the non-destructive test although some minor damage to the structure may be involved. An important feature of non-destructive test is that the place where test is done can be used for re-testing. The use of non-destructive tests has increased the safety level of construction and also helps in improving the scheduling of construction. All this increases the speed of construction besides keeping the economy of construction in considerable limits.

Definition:

These tests can be categorized in two parts:

1. Tests used to determine the strength of concrete
2. Tests used to determine the other characteristics of concrete like voids, cracks etc

Non destructive tests are the representation of relation between the property of structure which is being tested and the strength of test specimen. These tests are usually done in case of disputes between the parties which are involved in construction of any type of structure. Clients usually ask to conduct the test of strength of concrete which is being used in the structure.

The most common tests which are usually conducted are:

Rebound Hammer Test

It is one of the oldest non destructive test. This test is widely used because of its economical procedure

Penetration Resistance Test

In this test resistance to the penetration of steel rod in the concrete is used as the strength value

Ultrasonic Pulse Velocity Test

This test has automatic program apparatus. Apparatus is just placed on specimen. The waves pass through the specimen. Time taken by waves to reach from one end of specimen to other is considered to be the strength of specimen. Less the time taken, weaker will be the specimen and vice versa)

Pull out Test

This test measure the strength of specimen by means of special tension jacks that are usually used to be inserted in test specimen