ABSTRACT
Assessing the concrete compressive strength of the existing reinforced concrete (RC) structures by testing cores is the most reliable and effective method. However, the question that commonly arises concerning this method is the degree of representativeness of the test results. In this paper, a total number of 241 cores of current concrete material (C25/30 and C30/37 concrete class) was tested. The effect of core diameter (Ø =100 mm, 75 mm, 50 mm) for double length-to-diameter (l/d) ratio and maximum aggregate size (Dmax = 25 mm, 16 mm, 8 mm, 4 mm) on the compressive strength of cores has been studied. For the two concrete classes studied, test results showed a decrease of core compressive strength with the increase of the maximum aggregate size. Conversely, the compressive strength of the core is increased as the diameter is increased. The effects of the two parameters are less pronounced for the C30/37 concrete class.
