Abstract
NDT OF RC BEAMS WITH OLD CONCRETE AS PARTIAL REPLACEMENT OF NATURAL COARSE AGGREGATES BY REBOUND HAMMER
Mahboob Oad*, Abdul Hafeez Buller, Bashir Ahmed Memon and Noor Ahmed Memon
ABSTRACT
Need of residential and commercial space particularly in city centers around the world is growing every day. Therefore, pace of construction of high rise buildings is increasing at faster rate. Space constraints require demolishing of short height buildings to erect high rise buildings. This leads to huge quantum of demolishing waste. One way of treating this waste is to use it in new construction. Strength evaluation of concrete is the key parameter to ensure the quality of concrete. Destructive testing for evaluation of concrete strength is time consuming. Nondestructive testing on other hand provides easy and economical solution to the problem. Therefore, this research paper presents nondestructive testing of reinforced concrete beams made with 50% replacement of natural coarse aggregates with coarse aggregates from old concrete by rebound hammer test method. 96 reinforced concrete beams are cast and tested. The compressive strength obtained from rebound hammer test is then converted into flexural strength using ACI formulation. Comparison of obtained results with results of control specimen shows reliability of nondestructive testing for beams made with old concrete as partial replacement of coarse aggregates.
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