Effect of cold joint on compressive and tensile strength of concrete

This study aims to understand the effect of tensile and compressive stress on concrete with cold joint problem. A series of tests were designed in the context of this study. 4 different concrete grades (10, 20, 25, 30MPa) were selected and concrete grades demonstrate the very low grade, low grade, minimum grade according to Turkish Earthquake Code 2007 (TEC2007), minimum grade according to Turkish Earthquake Code 2018 (TEC2018) and normal grade concrete. In addition to the concrete grades, cold joint angle is also a parameter to be investigated. Zero angle will be the control angle since in this case the cold joint will be under fully compression. Besides, 20,45,65 and 90 degrees will be studies to understand the effect of cold joint angle on tensile and compressive strength capacity of the concrete. The results showed that samples with a resistance of 20, 25 and 30 MPa that have a cold joint with a zero angle have results close to the standard samples. Samples that have a cold joint at an angle of 90 with the same resistance had high results but less than the angle of zero. Samples with a cold joint at angle of 20 and 45 were ranked third in terms of resistance after samples that had a cold joint with angle of 0 and 90 and had similar behavior and close results. While samples with cold joint 65 were very weak. As for samples that have compressive strength 10, there is no effect of cold joint due to weakness of concrete. As for the effect of cold joint on tensile strength of samples with resistance 20o, 25o and 30o, samples at angle of 0o, 20o, 45o and 65o gave close results, however samples at angle of 90o gave the lowest resistance. Keywords: Angle of Concrete Joint, Cold Joint, Compressive Strength, Tensile Strength.