Method and apparatus for measuring early-stage autogenous shrinkage of cement-based material

Abstract

The invention discloses an apparatus for measuring early-stage autogenous shrinkage of a cement-based material. The apparatus comprises a test piece die, a pre-embedded target and a displacement measurement system, wherein the test piece die comprises an outer die and an inner die, the outer die is a box-like cuboid with an open upper end, the inner die is a rectangular frame which can be accommodated in the outer die, corresponding positions of two opposite end faces of the outer die and two opposite end faces of the inner die are respectively provided with a circular through hole, the pre-embedded target comprises an internal thread open tube and a threaded rod mutually fitting, the threaded rod can pass through the circular through holes in the inner die and the outer die, the displacement measurement system is a non-contact displacement measurement system and comprises a displacement sensor and a displacement signal acquisition and processing unit, and the displacement sensor can monitor displacement of the pre-embedded target and transmits monitored displacement information to the displacement signal acquisition and processing unit for processing. The invention further discloses a method for measuring early-stage autogenous shrinkage of the cement-based material. According to the invention, testing can be carried before prehardening, and the apparatus has the advantages of a simple structure and low cost.

Description

technical field [0001] The invention relates to a device and method for measuring autogenous shrinkage at early age of cement-based materials, and belongs to the technical field of cement material performance measurement. Background technique [0002] With the continuous progress and development of society, the performance requirements of concrete and other cement-based materials are getting higher and higher in actual engineering. At the same time, cracking during construction caused by high shrinkage of high-performance concrete is becoming more and more common. The cracking of concrete structure will greatly weaken or even seriously lose its durability, long-term mechanical properties, overall performance and aesthetic performance, which is one of the main reasons affecting the safety and durability of the project. Therefore, in order to effectively reduce and control autogenous shrinkage and improve its durability, the first problem to be solved is to establish an accura...

AI Technical Summary

Problems solved by technology

[0005] The technical problem to be solved by the present invention is to overcome the deficiencies of the existing cement-based material self-shrinkage measurement technology, and provide a cement-based material early-age self-shrinkage measurement device and measurement method, which can be deformed after the cement-based material is slightly plastic The measurement can measure the self-shrinkage of cement-based materials from super early age to hardening, and at the same time can more accurately determine the equivalent initial setting time, so as to more accurately determine the starting time of self-shrinkage, which is the early mechanical and deformation properties of cement-based materials. Research and numerical simulation analysis provide accurate self-shrinking technical parameters

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