Device and method for testing material creep under coupling action of tensile stress and environment

A testing device and tensile stress technology, applied in the direction of applying stable tension/pressure to test the strength of materials, etc., can solve the problems that it is difficult to use gravity or lever loading methods, limit the correlation of cement-based materials, and affect the spring stress, etc., to achieve Ensure effective delivery, reduce restrictions, and improve accuracy

Inactive Publication Date: 2013-08-28
SOUTHEAST UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] Combining the existing literature on the creep and deformation of cement-based materials, it is not difficult to find that most of the existing loading devices use spring loading, and there is no effective method to keep the stress constant during the test.
There are two main reasons: ①During the test, the material is constantly deformed, which direc

Method used

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  • Device and method for testing material creep under coupling action of tensile stress and environment
  • Device and method for testing material creep under coupling action of tensile stress and environment
  • Device and method for testing material creep under coupling action of tensile stress and environment

Examples

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Effect test

Embodiment 1

[0051] Mixing ratio of cement asphalt mortar (kg / m 3 ): dry powder 1000, emulsified asphalt 160, water 110, water reducer 1.4, defoamer 0.05. According to the above ratio, after using a forced mixer to mix well, pour the freshly mixed cement asphalt mortar into a dumbbell-shaped mold of a certain size, and then put the test piece into the standard curing room (temperature T =20±3℃, RH ≥95%) in the maintenance to the specified age and then taken out. Use the MTS810 testing machine to test the tensile strength of the cured specimens referring to GB / T 228.1-2010 "Metallic Materials Tensile Test Part One: Room Temperature Test Method". According to the measured tensile strength, using the testing device and testing method of the present invention, respectively apply 0.03, 0.15 and 0.30 stress levels (applied tensile stress / ultimate tensile stress) to the test piece, the control environment temperature is 20 ℃, relatively Humidity RH=60%. After the loading is completed, the st...

Embodiment 2

[0054] Mixing ratio of cement asphalt mortar (kg / m 3 ): dry powder 1000, emulsified asphalt 160, water 110, water reducer 1.4, defoamer 0.05. According to the above ratio, after using a forced mixer to mix well, pour the freshly mixed cement asphalt mortar into a dumbbell-shaped mold of a certain size, and then put the test piece into the standard curing room (temperature T= 20±3℃, RH≥95%) in the maintenance to the specified age and then taken out. Use the MTS810 testing machine to test the tensile strength of the cured specimens referring to GB / T 228.1-2010 "Metallic Materials Tensile Test Part One: Room Temperature Test Method". According to the measured tensile strength, adopt the test device and test method of the present invention to apply 0.030 stress level (applied tensile stress / ultimate tensile stress) to the test piece, and set the target temperature of the heating device to be 20°C, 40°C and 80°C, set relative humidity RH =60%. After the loading is completed,...

Embodiment 3

[0057] Mixing ratio of cement asphalt mortar (kg / m 3 ): dry powder 1000, emulsified asphalt 160, water 110, water reducer 1.4, defoamer 0.05. According to the above ratio, use a forced mixer to mix well, then pour the freshly mixed cement asphalt mortar into a dumbbell-shaped mold of a certain size, and then put the test piece into a standard curing room (temperature 20±3°C, RH≥95%) Maintain it to the specified age and then take it out. Use the MTS810 testing machine to test the tensile strength of the cured specimens referring to GB / T 228.1-2010 "Metallic Materials Tensile Test Part One: Room Temperature Test Method". According to the measured tensile strength, adopt the test device and test method of the present invention to apply 0.030 stress level (tensile stress / ultimate tensile stress) to the test piece, the setting temperature is 20 ℃, and the relative humidity of the preparation control is respectively 33%, 75%, 59% and 98% supersaturated inorganic salt solutions. A...

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Abstract

The invention discloses a device for testing material creep under the coupling action of tensile stress and the environment. The device comprises a support, a weight, a heating jacket, a container containing a saturated inorganic salt solution, a strain demodulator, a power supply, a temperature controller, a strain sensor and a test piece, wherein the support comprises a positioning plate, an upper spherical hinge, an upper clamping head, a supporting rod, a bearing plate, a base plate, a lower clamping head and a lower spherical hinge; the supporting rod is connected with the bearing plate through a sliding bearing; the test piece is embedded in a groove in the upper clamping head and a groove in the lower clamping head; the weight is positioned on the bearing plate; the heating jacket covers on the outer side of the support; the container is positioned between the support and the heating jacket; the strain sensor is adhered to the outer wall surface of the test piece; and the temperature controller is connected with the ring-shaped heating jacket. By adopting the device, the reliability of the test process can be improved, and the accuracy of results is ensured. Meanwhile, the invention also discloses a test method for the test device. The method is simple and easy to operate, and can keep that the test piece does not generate stress relaxation in the process of long-term load application, and the stress is uniformly distributed.

Description

technical field [0001] The invention belongs to the technical category of material durability testing, and specifically relates to a testing device and a testing method for material creep under the coupled action of tensile stress and environment. Background technique [0002] For half a century, accidents caused by insufficient durability of cement-based materials have continued to increase, especially major projects such as dams, roads, bridges, ports, and high-rise buildings that have not reached the design life. Economic losses and casualties. The creep phenomenon of cement-based materials is one of the main reasons for the decrease of structural bearing capacity, premature structural failure and shortened service life. Although there have been decades of research on the creep of cement-based materials, most of the research work is to consider the creep development law under the action of a single environmental damage factor, and most of the creep loads are compressive ...

Claims

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Application Information

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IPC IPC(8): G01N3/14
Inventor 陈惠苏邱克超孙璐
Owner SOUTHEAST UNIV
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