commercial concrete;  axial tensile strength;  Whenever it goes

In the early stage of concrete hardening, non-load cracks are easy to occur because the shrinkage strain and shrinkage stress of concrete are large at this time, but the tensile strength is relatively low. In order to obtain a more accurate early tensile strength of concrete, the self-designed concrete axial tensile test device was used to successfully solve the problem of difficult alignment of specimens, and the axial tensile strength tests of 20 d, 40 d, 60 d and 3 d of C3, C7 and C14 three strength grades of commercial concrete were carried out, and the test results were not discrete, and then the law of the early axial tensile strength of commercial concrete with time and its relationship with the compressive strength of the cube were obtained. The relationship between axial tensile strength and splitting strength of commercial concrete is discussed, and it is found that the conversion coefficient between the two in the specification is biased and safe.