Cracking load determination method of concrete fracture test based on acoustic emission technique

Abstract

The invention discloses a cracking load determination method of a concrete fracture test based on an acoustic emission technique. A three-point bending concrete beam is measured, an acoustic emission sensor and a load sensor are adopted, the acoustic emission sensor is connected with an acoustic emission collection device, and the load sensor is connected with a load-strain collection device. The cracking load determination method comprises the following steps of pasting the acoustic emission sensor on the surface of the three-point bending concrete beam, and putting the load sensor in a position, to which load is applied, of the three-point bending concrete beam, wherein the acoustic emission sensor is perpendicular to the surface of the three-point bending concrete beam; applying load to the three-point bending concrete beam, and recording the load as cracking load of the three-point bending concrete beam when the interior of the three-point bending concrete beam begins to crack. According to the cracking load determination method of the concrete fracture test based on the acoustic emission technique, the cracking load of the concrete fracture test can be more precisely determined.

Description

technical field [0001] The invention relates to a method for determining the initiation load of a concrete fracture test based on acoustic emission technology. Background technique [0002] In the evaluation of the stability of crack propagation of hydraulic concrete buildings and the anti-cracking and anti-cracking design of hydraulic concrete buildings, it is necessary to provide concrete fracture toughness parameters. In order to unify the test method of concrete fracture toughness, the national development The National Development and Reform Commission issued the "Notice of the General Office of the National Development and Reform Commission on Printing and Distributing the 2005 Industry Standard Project Plan" (Fagaibongye [2005] No. 739). On the basis of extensive collection of concrete fracture test data at home and abroad, referring to the fracture test standards of developed countries in the world, conducting a large number of parallel tests, holding expert group dis...

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Problems solved by technology

It is difficult to determine the nonlinear starting point of the rising section of the F-CMOD curve. Even if it is determined by local amplification, the judgment error is still large, so it is difficult to use this method to judge the crack initiation load

[0008] The patent "a test method for crack initiation load of steel fiber concrete fracture test" adopts the method of testing the displacement change of the notched beam to test the crack initiation load; the patent "test method of crack initiation load for concrete fracture test" uses strain gauges to test the crack initiation load Both methods can test the crack initiation load of concrete fracture test very well, but the two methods have the same shortcomings, that is, the two methods only test the crack initiation load value when the surface of the concrete specimen is cracked, and the actual During the test process, in most cases, the cracking of the concrete specimen is first cracked from the inside and then expanded on the surface of the concrete specimen. Therefore, the results of the crack initiation load measured by the above two methods are relatively lagging behind, and the test load value is also relatively large

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