Method and device for measuring mechanical property of cement-based material

Abstract

The invention discloses a method for measuring mechanical property of a cement-based material. By the method, dynamic modulus of elasticity and poisson ratios of a cement-based material at all age times can be synchronously calculated according to transmission speeds of ultrasonic transverse waves and ultrasonic longitudinal waves by continuously measuring the transmission speeds of the ultrasonic transverse waves and the ultrasonic longitudinal waves in a cement-based material test piece to be measured at all the age times. The invention also discloses a device for measuring the mechanical property of the cement-based material. The device comprises a cubic test die with an opening at the upper part, an ultrasonic longitudinal wave emitter, an ultrasonic longitudinal wave receiver, an ultrasonic transverse wave emitter, an ultrasonic transverse wave receiver and an ultrasonic wave signal processing unit, wherein the cubic test die is used for pouring the cement-based material test piece to be measured; the ultrasonic longitudinal wave emitter and the ultrasonic longitudinal wave receiver are symmetrically arranged in two side walls of the cubic test die; the ultrasonic transverse wave emitter and the ultrasonic transverse wave receiver are symmetrically arranged in the two side walls of the cubic test die; and the ultrasonic wave signal processing unit is connected with the ultrasonic longitudinal wave emitter, the ultrasonic longitudinal wave receiver, the ultrasonic transverse wave emitter and the ultrasonic transverse wave receiver respectively. The dynamic modulus of elasticity and the poisson ratios of the cement-based material in the early age can be measured nondestructively.

Description

technical field [0001] The invention relates to a method for measuring the mechanical properties of cement-based materials, in particular to a method and device capable of nondestructively and synchronously measuring the dynamic elastic modulus and Poisson's ratio of cement-based materials at an early age. Background technique [0002] The problems involved in the early cracking of concrete structures are comprehensive and complex, covering all aspects of early thermal, mechanical and deformation properties of cement-based materials. The application of mineral admixtures and admixtures also greatly increases the complexity of its early performance. Researchers at home and abroad have conducted a large number of experimental studies on the early macroscopic properties of concrete, trying to clarify the early cracking mechanism of concrete, the law of early performance changes and the selection of technical parameters. Among them, the development and change process of cement-b...

AI Technical Summary

Problems solved by technology

Among them, the development and change process of cement-based materials' early elastic modulus and Poisson's ratio with age is one of the hot issues concerned by researchers, and it is also an important parameter necessary for the formulation of temperature control and crack prevention measures. The method of elastic modulus should be carried out at least one day after the sample is poured and the formwork is removed, so it is difficult to measure the earlier elastic modulus of cement-based materials by traditional methods

At present, some non-destructive methods for measuring the early elastic modulus of cement-based materials need to be demoulded for measurement after one day, and it is impossible to monitor the development and change of elastic parameters in earlier ages, especially before and after initial setting.

In addition, the Poisson's ratio in the early age of cement-based materials fluctuates widely, and it is obviously inaccurate to use it as a fixed value in existing research.

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