COMPRESSIVE STRENGTH OF CONCRETE USING INNOVATIVE IN-SITU SHEAR TESTING METHOD

Shear strength is the essential mechanical property of structural concrete, especially for complex stress analysis and finite element analysis. Laboratory core double shear testing (LDST) is considered time-consuming and expensive testing for the measurement of the in-situ shear strength of concrete. The object of this paper is to introduce an innovative in-situ shear test (IST) method for the measurement of the shear strength of partial concrete cores. According to the principle of the clamping mechanism, the time required for field testing was reduced to less than 30 minutes. The core samples in different diameters and lengths were compared by IST and LDST. Student's t-tests of shear strength results obtained by using LDST and IST showed an evident difference between the two methods. The shear strength of the core increases with the decrease of the core length and increases with the core diameter. The standard deviation of the results was considered as an increase with a reduction of core diameter for both LDST and IST. Since no extraction of core specimen is needed, and the core length is less than that of tested using LDST, and the specimens can be easily carried and quickly performed in-situ with less damage to the structure. The shear strength of concrete measured by IST is inferior to that of obtained by the LDST method, and correction efficiency must be adopted to adjust IST test results to that LDST. A good correlation between concrete IST strength and cube compressive strength is proposed in the paper.