Assessment of insitu concrete, a major building material in civil construction has been of considerable interest in Construction Industry both for quality control as well as to find residual strength. The measurement of strength & other performance parameters is generally done by normal destructive tests. However load or core tests is many time not possible or practicable. Since last decade, non-destructive testing have found wide acceptance throughout the world to assess the quality of insitu concrete. Techniques includes Rebound hammer, Ultrasonic tests, Penetration tests, radiography tests etc. However none of these test techniques can be used independently to yield reliable quantitative results. Generally combination of a few Non-destructive test yields results of acceptable levels. A number of Correlation between Rebound hammer test and Ultrasonic pulse velocity test results have been developed to use both methods and obtain reliable results. Recently a combination of NDT techniques like Rebound hammer, Ultrasonic pulse velocity and windsor probe has been used to evaluate the quality of few distressed structures, an office building of local corporation and another court building in Gujarat, successfully to recommend their restoration. Supplementary core test results confirmed the reliability of the correlation between the different NDT techniques used. The paper presents the evaluation of the quality of above two structures using NDT techniques.
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