Abstract
NON-DESTRUCTIVE TESTING OF RC BEAMS MADE WITH PARTIAL REPLACEMENT OF COARSE AGGREGATES FROM DEMOLISHED CONCRETE EXPOSED TO FIRE
Abdul Hafeez Buller*, Mahboob Oad and Bashir Ahmed Memon
ABSTRACT
Population growth particularly in city centers around the globe have forced the construction industry to build high rise structures in place of old and short height buildings. This on other hand led waste disposal crisis. An approach to reduce these crises is to reuse the demolishing waste in new construction. Therefore, this research work used 50% replacement of natural coarse aggregates with coarse aggregates from demolished concrete. Generally, quality of concrete is estimated by measuring its strength. Laboratory testing of strength is time consuming therefore, non-destructive test methods provide good alternative to destructive testing. In this research work rebound hammer tests are used to estimate the compressive strength of reinforced concrete beams made by 50% replacement of coarse aggregates with coarse aggregates from old demolished concrete. 48 RC beams are cast using normal and rich mix concrete. 12 beams are cast using all-natural aggregates to compare the results of proposed beams. After curing of 28-days in standard manner rebound hammer is used to measure the compressive strength of the beams, followed by exposing the beams to fire for 6- and 12-hours at 1000?C in purpose made oven. The comparison of results with control specimen shows that proposed beams has good fire resistance and can be used initially in areas of low load.
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