Measuring system for self-constriction of early-age concrete

Abstract

The invention relates to a measuring system for self-constriction of early-age concrete. The measuring system comprises a concrete test piece, an intelligent curing box and a computer with control software, wherein the concrete test piece is externally provided with the intelligent curing box which is used for controlling the concrete test piece to be in a temperature constant state; the two sides of the intelligent curing box are provided with laser displacement meters and brackets of the displacement meters; and a base is arranged at the bottom of the intelligent curing box. The measuring system has the beneficial effects that the volume change and deformation of the early-age concrete can be measured effectively, and in particular can realize the accurate measurement on self-constriction deformation beginning from the finishing moment of casting; as the concrete test piece is in the preset temperature constant state all the time, the influence of the temperature change of the concrete to the self-constriction is eliminated, and the temperature deformation of the concrete does not need to be reduced; the laser displacement meters are used for measuring the self-constriction deformation, the accuracy is high, and the influence of environments is low; both the hardware setting and the measurement process monitoring can be realized by the computer and the software, so that the errors of manual operation and recording can be effectively reduced, and the degree of automation of the whole system can be improved; and in addition, consumable materials in the whole system are few, and most of parts can be used repeatedly.

Description

Technical field [0001] The invention relates to the field of concrete materials, in particular to a system for measuring the autogenous shrinkage of concrete at an early age. Background technique [0002] Self-drying and self-shrinkage are important characteristics of concrete materials, especially high-strength, high-performance concrete during the setting and hardening process. If the control is not effective, it is very easy to cause early cracking of the concrete before it is subjected to external loads. Once the concrete cracks, its durability, long-term mechanical properties, integrity and aesthetics will be greatly weakened, or even severely lost. In order to effectively reduce and control autogenous contraction, the first problem to be solved is to establish an accurate and effective method for measuring autogenous contraction. [0003] For hardened concrete, a variety of mature and stable autogenous shrinkage measurement methods have been established, and some of these m...

AI Technical Summary

Problems solved by technology

However, for concrete at an early age (initial setting and hardening), there is no uniform standard method for the measurement of autogenous shrinkage, and it is not advisable to directly apply the measurement method of hardened concrete

Although there are many methods scattered in various literatures and patents, most of them have the disadvantages of late age measurement (after final coagulation), high control requirements, and many influencing factors. Among them, the method proposed by Japanese scholars uses low elasticity Embedded strain gauges of modulus are an accurate and effective method for measuring early autogenous shrinkage, but they have been criticized because such embedded strain gauges are too expensive and cannot be reused

Another common defect of the existing early age autogenous shrinkage measurement method is that the thermal expansion coefficient of concrete is regarded as a constant value when deducting the temperature deformation from the total deformation, which is very different from the actual situation, that is, the measured "autogenous shrinkage "shrinkage" is not simply self-shrinkage

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