DEVELOPMENT OF CORRELATION BETWEEN CORE-CYLINDER-CUBE STRENGTH OF CONCRETE

Abstract

Concrete cores play an important role in the quality control measurement and strength assessment of existing structures. The objective of this experimental study was to determine the influences of reinforcement parameters such as bar diameter, number and position of reinforcing bars from top edge of the core on the concrete cores strength and also to discuss the effect of core diameter and strength level of concrete on concrete core strength. A total of 110 cores and 63 standard cylinders and cubes were tested in this investigation. The results on reinforced cores indicate that the presence of reinforcing bars reduce the strength of concrete core ranging from 2.85 to 15.99 percent. The reduction is high when multiple bars were present in the core comparison to the single bar. The test results for unreinforced cores indicate that strength Correction factor increases with decrease in the diameter of core with same 1/d ratio. For example when 55 and 76 mm cores with 1/d ratio of 1 and 2 were considered, correction factors were found to be 1.05, 1.03 for cores with 1/d ratio of I and 1.07, 1.03 for cores with 1/d ratio of 2. A comparison with the BS 1881: Part 120 [1] based prediction of the correction factors of reinforced concrete core is presented.