Brittle building material testing device and test method thereof

Abstract

The invention discloses a brittle building material testing device and a test method utilizing the same. A main body of the testing device is a mechanical testing machine, wherein the mechanical testing machine is provided with a test block fixing frame used for fixing a test block and a bending load loading device; an output shaft of the bending load loading device is provided with a time encoderin a sleeving manner; in addition, a plurality of high-accuracy CCD cameras, facing test block mounting positions on the test block fixing frame, are also fixedly connected to the side of a base; meanwhile, a plurality of elements and a database are connected with data of a multi-interface controller to realize data encoding and processing. By adopting the testing device, a three-point bending test is performed on a test block through the mechanical testing machine; in the process, the bending load loading device is utilized to perform variable load loading; the high-accuracy CCD cameras areutilized to collect data, and the data is stored after being collected and encoded. The testing device provided by the invention ensures that eccentric tension and twisted tension cannot occur in a tension process and can more accurately test the direct tension ultimate strength of a brittle material and obtains an accurate crack image.

Description

technical field [0001] The invention belongs to the technical field of testing mechanical properties of materials, in particular to a testing device and a testing method for brittle building materials. Background technique [0002] Generally speaking, commonly used brittle materials for construction mainly include rock, concrete, ceramics, glass, etc. This type of brittle material is widely used in the construction process of various large-scale construction projects, and its mechanical properties affect the overall structure of these projects. Safety. Therefore, many research institutions and scholars have carried out a lot of research on the fracture behavior of rock, concrete and various other types of brittle materials, including the establishment of fracture models that can describe their characteristics, and the use of various macro and micro numerical simulation methods to simulate cracks. However, no matter what method is used for simulation, it is necessary to obta...

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Problems solved by technology

[0003] However, the common brittle materials are compressive but not tensile, and their failure areas often start from the tensile stress area, and different brittle materials have different failure characteristics, resulting in uncertain fracture locations of brittle materials in direct tensile tests. The monitoring of deformation by strain gauges and other methods is inaccurate and cannot reflect the true tensile strain of brittle material samples. At the same time, as brittle materials, rocks and concrete will fracture with only a small deformation under the action of external force, and these fractures occur The damage strain is usually in the range of hundreds of microstrains, which is difficult to observe. In general, the crack widths that cause local damage to rock and concrete materials are all above 10 μm. Significantly, this combination of small and observable deformations makes it difficult to test brittle failure processes in geotechnical materials

Taking the tensile performance test of rock as an example, the main method to study the tensile mechanical properties of rock is the Brazilian split test, which is an indirect method to obtain the tensile mechanical properties of rock, but there is a certain gap between the results and the direct tensile results of rocks , through direct observation or monitoring with strain gauges or displacement sensors, there is a certain degree of deviation, and it is difficult to obtain the subtle deformation of brittle materials under the action of external force

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