ULTRASONIC PULSE VELOCITY TEST
IS:516(Part-5: Sec-1) 2018
Testing plays an important role in controlling the quality ofcement concrete work. Systematic testing of the raw materials, the fresh concrete and the hardened concrete, is an inseparable part of any quality control programme for concrete. This helps achieve a higher efficiency of the materials used and greater assurance of the performance of the concrete, in regard to workability, strength and durability. The test methods used should be simple, direct and convenient to apply. This standard was prepared with this objective in view.
This standard was first publishedin 1959. In this first revision, it was decided to review and update the various existing test methods of concrete. The revision of the standard is being brought out taking into consideration the latest international practices and developments in this field in the country, and also introduced certain new test methods wherever required. In the process, the various existing test methods covered in IS 516:1959 ‘Methods of tests for strength of concrete’ have been revised taking into consideration primarily the corresponding ISO standards while also examining the other best practices world over and in the country. In addition, test methods for determination of additional properties have been included in areas such as permeability, initial surface absorption, corrosion of reinforcement, carbonation of concrete (field test), accelerated carbonation test, and creep of concrete. Also, for better understanding and implementation, some of the other test methods which were spread over in number of other Indian standards have been brought together under the fold of IS 516 as its various parts, such as the splitting tensile strength, ultrasonic pulse velocity test, rebound hammer test,pull out test for bond in reinforced concrete, and determination of water soluble and acid soluble chlorides. This is with a view to making the standard complete in all respects, and rendering it a comprehensive source of provisions for testing of concrete and reference in other Indian Standards.
SCOPE
This standard covers the object, principle, apparatus and procedure of rebound hammer test method. In addition, influence of test conditions and some general guidance on the interpretation of test results are also given. NOTE - In view of the limitations of each method of non-destructive testing of concrete, it is essential that the results of tests obtained by one method .should be complimented by other tests and each method should be adopted very carefully.
REFERENCES
The following Indi‘an standards are necessary adjuncts to this standard. IS No. Title 516 : 1959 Method of test for strength of concrete Table 1 Impact Energy for Rebound Hammers for Different Applications ( Clause 4.1 ) Sl No. Application Approximate Impact Energy Required 8900 : 1978 Criteria for rejection of outlying observations
OBJECT AND PRINCIPLE OF TEST
301 Object
The rebound hammer method could be used for:
i) assessing the likely compressive strength
of concrete with the help of suitable corelations between rebound index and
compressive strength,
ii) assessing the uniformity of concrete,
iii) assessing the quality of the concrete in
relation to standard requirements, and
iv) assessing the quality of one element of
concrete in relation to another.
3.2 Principle of Test
When the plunger of rebound hammer is pressed against the surface of the concrete, the spring controlled mass rebounds and the extent of such rebound depends upon the surface hardness of concrete. The surface hardness and therefore the rebound is taken to be related to the compressive strength of the concrete. The