Measuring apparatus for rate of self-contraction of cement concrete

Abstract

This invention relates to concrete self contract meter in architecture materials field, which comprises amesdial and specimen mold, which is characterized by the following: the mold is fixed with one amesdial and the mold is composed of top cover, down cover ad hollow round disc, wherein, the disc bench axis line passes the amesdial long bar for overlapping with an angle foralpha=45-60degree between mother line and bottom line; The mold is inserted with resistance stress slice and temperature sensor probe; the stress slice wires are connected to stress device and the probe is connected to temperature meter.

Description

technical field [0001] The invention belongs to the field of building materials, and relates to a device for measuring the early self-shrinkage rate of cement mortar and concrete. Background technique [0002] The autogenous shrinkage of cement concrete refers to the volume reduction caused by the hydration of the concrete after the initial setting under the condition of constant temperature and humidity. The autogenous shrinkage does not include drying shrinkage, cooling shrinkage, carbonation shrinkage, etc. The autogenous shrinkage of high-strength concrete accounts for a high proportion of the total shrinkage, so autogenous shrinkage must be controlled. Accurate, simple and convenient testing of the autogenous shrinkage of concrete is the basis for the study of autogenous shrinkage, but there is no unified standard for the measurement of concrete autogenous shrinkage at home and abroad, and different measurement methods have different problems. For example, the self-shr...

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Problems solved by technology

[0009] (3) LVDT sensor: Use linear differential displacement sensors at both ends of the concrete specimen to monitor the deformation of the early volume of the concrete. This method is simple to operate and is less affected by human influence. sensor, and the test piece or sensor cannot be shaken during the measurement process, the cost is high

However, since the temperature linear expansion coefficient of concrete in the plastic stage is not a definite value, this will bring errors to the test results.

Another method is to carry out interlayer insulation treatment on the mold to provide a nearly adiabatic environment, but this method has high requirements on the mold and does not conform to the actual project

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