Test method for measuring fracture energy of concrete based on four-point bending beam

Abstract

The invention relates to a test method for measuring fracture energy of concrete based on a four-point bending beam. The test method comprises the steps of mounting a test device and a test piece, applying a load for testing, recording test data, calculating fracture energy and the like. The test method ensures that a stress state of the test piece is simply supported, and complete load-deflectioncurve can be obtained when an initial seam height ratio is greater than or equal to 0.4 according to a test result of an applicant, wherein an initial seam height ratio for measuring fracture energyby adopting a three-point bending beam test piece recommended by a Technical Committee on Fracture Mechanics of Concrete (TC-50FMC) of an International Union of Laboratories and Experts in Construction Materials, Systems and Structures (RILEM) is 0.5.

Description

Technical field [0001] The invention relates to a test method for measuring the fracture energy of concrete based on a four-point bending beam, and belongs to the technical field of material mechanical performance testing. Background technique [0002] At present, most of the testing of the fracture energy of concrete is based on three-point bending beam specimens. The RILEM Concrete Fracture Mechanics Committee (TC-50FMC) provides a standard test method for measuring the fracture energy of concrete based on three-point bending beam specimens. However, according to the test results of many scholars, when the three-point bending beam specimen is used to measure the fracture energy of concrete, the expansion path of the precast joint is often skewed due to the presence of large aggregates. According to the force of the three-point bending beam It can be seen from the state that once the crack appears deviated, the crack tip will be simultaneously affected by the bending moment and...

AI Technical Summary

Problems solved by technology

However, according to the test results of many scholars, when three-point bending beam specimens are used to measure the fracture energy of concrete, the expansion path of prefabricated joints is often deflected due to the presence of large aggregates. It can be seen from the state that once the crack is deflected, the crack tip will be subjected to both bending moment and shear force, and the existence of shear force will make the crack propagation path more deflected, so the measured concrete fracture energy will be affected by the crack. The deflection of the expansion path causes the actual fracture area to be larger than the fracture area used in the calculation, which leads to the measured concrete fracture energy not reflecting the real ability of the concrete material to resist fracture

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