NON-DESTRUCTIVE TECHNIQUES FOR QUALITY CONTROL AND ASSURANCE

摘要

Application of reinforced concrete is very high in the construction industry due to its inherent advantages. The quality of concrete depends on many factors and to achieve the desired quality of concrete the proportion of its constituents, method of placement, curing etc are to be supervised and controlled. An indication of the quality of concrete is normally had by the measurement of compressive strength of the standard cubes. In-situ strength of concrete may be required for knowing the strength of concrete being used and for checking the quality of concrete already in use. Strength of concrete can be tested by two methods Viz. Destructive and Non-Destructive tests. Non Destructive Testing (NDT) of Engineering materials, components and structures has steadily increased during the past few years at an unprecedented rate due to the all round thrust for improving material quality, component integrity and performance reliability. NDT is used for routine or condition monitoring of various items during operation to predict and assess the remaining life of the component while retaining its structural integrity. Rebound Hammer test and Ultra sonic pulse velocity tests are NDT methods, which are useful as a measure of uniformity of concrete and are of great value in checking the quality of the material throughout the structure, and are primarily used for comparative investigations. This paper discusses the various NDT methods employed in quality control of concrete with a particular reference to Schmidt Rebound Hammer and Ultra Sonic pulse tests. Some of the case studies are also presented in which the soundness of the existing concrete structures was evaluated.