20-10-2014, 12:18 PM
Abstracts: Reinforced concrete structures consist of various members having the load carrying capacity. Transfer of the load is done from the slab to beam then after from column to foundation. Concrete is the integral part of the structure, so it should be checked during and after construction for building safety purpose and if necessary various tests should be performed on it. This test could be performed under working condition if necessary. In past, Destructive method was used but now a day NDT proves to be a wise choice. NDT means NON DESTRUCTIVE TEST. Basic concept of NDT is to obtain concrete strength without any destruction. This test is used for determining the extent of cracks, voids, honeycombing, and defects within a concrete structure, locating suspected deteriorating of concrete and even for determining concrete uniformity. This method is very swift and the main advantage of NDT is that, no damage is caused to the concrete structure whereas in DESTRUCTIVE TEST it is done up to the breaking point of the concrete. Compressive strength of concrete can be obtained as guided in Indian standard IS 13311 Part 1 AND Part 2. But true strength or Actual strength of concrete can only be known by loading up to its failure load. The load at which the specimen will break will show its actual strength. Therefore to get actual strength of concrete specimen must undergo laboratory testing, where destructive tests are performed on it. But, this procedure may cause trouble and delay in judging the existing structures which indicates towards the selection of NDT. IN NDT following test are practiced. •Core test •In situ water permeability test •Chloride determination test •Carbonation depth measurement test •Cover meter test •Half cell potential test •Electrical resistivity test •Ultrasonic pulse velocity test •Rebound hammer test But this study performs ULTRASONIC PULSE VELOCITY (UPV), REBOUND HAMMER and CORE CUTTER on concrete members in field and even in laboratories. This study performs experiment on concrete members as stated in Indian standard IS 13311 and collects every test results, due to which various errors can be found in field. From these tests, relations are established between REBOUND HAMMER, COMPRESSIVE TEST MACHINE (CTM) and UPV in form of equations. Various equations are obtained for 14 days and 28 days strength from REBOUND HAMMER, CTM and UPV. All equations and graphs are generated by MATLAB computer software and errors in each equation are carried out manually to check the reliance and accuracy of equations. These equations will give you directly actual strength of specimen putting the value of NDT. Basic idea behind NDT is that you still have something at the end of the test which is use fully.