Low temperature crack resistance test method and equipment of building materials

Abstract

The invention relates to a test device and method for the low-temperature crack resistance performance of building materials. It consists of an ambient temperature control box, a freeze-off testing machine, and a measurement control system. During the definite cooling process, a high-precision displacement sensor is used to measure the distance between two fixed points on the test piece, and at the same time, the input displacement measurement system is pre-set on the reference test piece. The measured reference displacement is processed by a microcomputer to control the specimen stretching mechanism to pull the specimen back to its original length. Such continuous measurement and control keeps the specimen in the "zero displacement control" state, thus eliminating the need for specimen clamping systems and Measure the temperature shrinkage error and elastic deformation error of the system, so as to obtain the "freezing critical temperature" of the specimen under the pure temperature stress factor. The test equipment is equipped with three modified parts, which can complete the "relaxation", "creep", test items, and can also carry out the test items of "low temperature stretching" and "measurement of linear expansion coefficient". It can also be used for cement concrete and polymer composites. Material testing.

Description

technical field [0001] The invention belongs to the technical field of building material testing, and relates to a method for testing the low-temperature crack resistance of building materials, in particular to a method for testing the low-temperature crack resistance of asphalt materials. The invention also relates to equipment for realizing the test method. Background technique [0002] In the technical field of building materials, low-temperature cracking of polymer composite materials, cement concrete materials, asphalt concrete panels, and asphalt pavement is a common form of damage to buildings. Before the present invention, due to the lack of methods and corresponding equipment for correctly measuring the low-temperature cracking temperature of materials, indirect reasoning methods such as low-temperature ductility tests and low-temperature tensile tests were generally used to replace them. , can only qualitatively compare the low-temperature crack resistance of mater...

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Problems solved by technology

[0003] In view of the problems existing in the above-mentioned prior art, the purpose of the present invention is to change the obvious defects that the indirect reasoning and estimation methods such as low temperature ductility test and tensile test can only be qualitative but not quantitative, and provide a method that can accurately measure low temperature crack resistance. Temperature, to obtain the correct temperature-stress curve and accurate low-temperature cracking temperature, to eliminate the temperature deformation and elastic deformation of the clamped specimen frame to test the low-temperature crack resistance performance, and to provide special low-temperature crack resistance test equipment for implementing this method

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