Investigation of the effect of steel rebar, casting direction and moisture on determination of core compressive strength

According to increase the safety of buildings against earthquakes the importance of determining the compressive strength of concrete in situ is being increased day by day. For this reason, increasing the security of existing buildings is an important issue. In this study, it was aimed to determine the compressive strength of concrete in situ. In order to investigate the steel rebar, casting direction and moisture effect in determining the concrete core compressive strength, two 200 x 100 x 40 cm reinforced concrete and pure concrete blocks have been produced. On the 28th, 60th and 90th day of the produced blocks, 144 pieces of core samples, which are perpendicular, parallel to the casting direction 24 core samples with steel rebar and 24 without steel rebar with 93mm/93mm dimensions, were collected. Half of the taken cores were kept in the laboratory for three days and seconed half were cured in water for three days. At the end of the third day, all cores were subjected to a pressure test with a cap. As a result of the pressure test, core compressive strengths have been increased by the time. The compressive strengths of the cores cured in water were lower than the compressive strengths of the cores kept in the laboratory. The compressive strengths of the cores with and without steel rebars taken perpendicular were higher than the compressive strength of the cores taken parallel to the casting direction. At the same time, the compressive strength of cores with steel rebar which is perpendicular to the casting direction compared to the compressive strength of the cores without steel rebar is higher.