Concrete axis stretching creep tester and test method thereof

Abstract

The invention discloses a concrete axis stretching creep tester and a test method thereof. The tester comprises an upper pulling plate, a lower pulling plate, pulling bars, screws, a spring, a stress sensor and vibrating string extensometers, the pulling bars are fixed on the lower pulling plate, and the upper ends of the pulling bars are provided with thread ends; the upper pulling plate traverses the upper ends of the pulling bars and is sleeved on the thread ends, and the thread ends at the upper and lower sides of the upper pulling plate are provided with nuts to fix the upper pulling plate; the upper and lower pulling plates are provided with the screws respectively and are used for the fixed connection of the upper and lower end of a concrete test piece, and the vibrating string extensometers are arranged at two sides of the concrete test piece; and the screw on the upper pulling plate stretches out of the upper pulling plate, the spring is sleeved on the stretching end of the screw, the stretching screw is also sequentially sleeved with a pad and a nut, and the stress sensor is arranged between the pad and the nut. The tester and the method realize the continuous automatic detection and acquisition of deformation; and no eccentricity, concentrated stress and constant stress are realized in the stretching process, so the test accuracy is improved.

Description

technical field [0001] The invention belongs to the technical field of long-term deformation testing of concrete in the civil engineering and construction industry, and in particular relates to the measurement technology of axial tensile creep of concrete. Background technique [0002] Cement concrete is the most important building material today, widely used in construction, transportation, bridges, water conservancy, underground engineering and other fields. With the rapid development of the global economy and unprecedented construction scale, the amount of concrete used is increasing year by year, especially for China, which is experiencing rapid economic development. At present, the annual output of concrete in my country has reached 10 billion tons, accounting for more than 50% of the world's total output. [0003] As the most widely used material in civil engineering, concrete is a viscoelastic material with obvious timeliness, so under long-term loading, creep phenome...

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Problems solved by technology

[0005] However, since the discovery of concrete creep phenomenon, long-term research on concrete creep has been carried out at home and abroad, but the research focus has always been on the creep performance of concrete under long-term compressive stress, and the axial tensile creep characteristics Due to the small deformation of tensile creep and the difficulty of test work, there are not many studies carried out. In actual engineering, compressive creep is usually used instead of axial tensile creep, resulting in a decrease in the accuracy of stress analysis. , the analytical results can only be used qualitatively but not well for quantitative analysis

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