A device and method for evaluating the relaxation modulus of concrete under different curing conditions

Abstract

A device and a method for evaluating a relaxation modulus of concrete under different curing conditions are disclosed. The device comprises a template system, a temperature system, an acquisition system, a control system and a computer system; the template system comprises an experimental template and a control template, the experimental template and the control template both includes an upper template with a temperature control channel, a lower template and two symmetrical side templates, the upper template is provided with two quartz rods in a penetration manner, and a displacement sensor isarranged between the two quartz rods; the upper template, the lower template, the side templates, an end template and the center of a pouring space are provided with first temperature sensors respectively, the temperature system includes a water tank with a water pump, the water tank is internally provided with a temperature control device and a second temperature sensor; the input end of the acquisition system is connected with the displacement sensor, the first temperature sensor and the second temperature sensor, the output end of the acquisition system is connected with the input end of the computer system; the input end of the control system is connected with the output end of the computer system, and the output end of the control system is connected with the temperature control device and the water pump.

Description

technical field [0001] The invention belongs to the technical field of water conservancy and hydropower, in particular to a device and method for evaluating the relaxation modulus of concrete under different curing conditions. Background technique [0002] Concrete is a heterogeneous, brittle material whose tensile strength is much lower than its compressive strength. Due to the thick section of the hydraulic concrete structure, it is difficult to dissipate the heat of hydration of the cement, which leads to the tensile stress of the concrete under the condition of excessive temperature difference and internal and external constraints. Once the tensile stress exceeds its tensile strength, the concrete will crack, which will have a serious impact on the safety of the hydraulic structure during construction and operation. [0003] The relaxation properties of concrete can reduce the stress amplitude of concrete and reduce the risk of concrete cracking. Accurately grasping th...

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Problems solved by technology

[0004] (1) Since the relaxation test is cumbersome, the creep compliance obtained from the creep test is mostly used at present, and the relaxation modulus is obtained after solving the Volterra integral equation, but the conversion process is relatively complicated, and too many parameters of the relaxation modulus are obtained , not easy to use;

[0005] (2) Based on the creep coefficient obtained from the creep test, the expression of the relaxation modulus is obtained by an explicit solution, which also has the problem of too many parameters in the formula;

[0006] The above two methods need to obtain the relaxation modulus value of concrete with the help of complex numerical calculations on the basis of known creep history, which is not convenient for engineering and technical personnel to estimate the stress development degree of concrete on site

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