Noncontact-type test method of early-period thermal expansion coefficient of concrete dam and equipment thereof

Abstract

The invention relates to a noncontact-type test method of an early-period thermal expansion coefficient of a concrete dam and equipment thereof. The test method comprises the following steps of: (1) loading a piece to be tested in a culture test barrel; (2) arranging a metal test terminal at the top of the piece to be tested and immediately putting the tested piece in a constant-temperature waterbath to culture; (3) stabilizing for a period of time, slightly increasing the temperature, confirming a test end point when the internal temperature of the piece to be tested is constant with the water temperature, then decreasing the temperature to a start temperature and circulating; (4) testing the displacement values of the bottom and the top of the piece to be tested with a noncontact-type laser displacement sensor; and (5) calculating the early-period thermal expansion coefficient of the piece to be tested according to tested displacement change data. The equipment comprises the culture test barrel containing the piece to be tested, a constant-temperature water bath case is arranged outside the barrel, the culture test barrel is internally provided with the metal test terminal which is pre-buried at the top end of the piece to be tested, and the noncontact-type laser displacement sensor is arranged on the culture test barrel. The invention overcomes the defects of the prior art and provides a noncontact-type in-situ displacement test to acquire the early-period thermal expansion coefficient of the concrete dam.

Description

technical field [0001] The present invention relates to the early stage thermal performance testing technology of dam concrete, in particular to a non-contact method and equipment for testing the early stage thermal expansion coefficient of dam concrete. Non-contact test method for early thermal expansion coefficient of dam concrete. Background technique [0002] The thermal expansion coefficient is one of the main thermophysical parameters of concrete, and it is also an important characterization parameter of its volume stability; the thermal expansion coefficient of dam concrete is generally characterized by the linear expansion coefficient, which is required by the "Hydraulic Concrete Test Specification" (SL 352-2006) The test piece should be cured for at least 7 days before the test. At the same time, it is allowed to use the test piece that has been tested for the volume deformation of the concrete itself. Therefore, the thermal expansion coefficient of the concrete in ...

AI Technical Summary

Problems solved by technology

Routine testing of the thermal expansion coefficient of concrete requires a large temperature rise on the specimen (for example, the "Hydraulic Concrete Test Specification" requires a temperature rise of about 40°C), which significantly affects the early hydration of concrete, making the test results deviate from the hydration age , a group of specimens can often only test the thermal expansion coefficient of a certain age, and it is difficult to continuously test the thermal expansion coefficient of the same group of specimens at different ages; at the same time, due to the low strength of the early dam concrete, the conventional contact length measurement method is used It is difficult to guarantee the accuracy of the results

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