SU1052968A1 - Method of determining layer moisture loss of concrete - Google Patents

Abstract

A METHOD FOR DETERMINING LATERATED WATERPROOF CONCRETE in the process of keeping in shape, including measuring the electrical resistivity of the layers, is also different from the fact that, in order to simplify, improve the accuracy and speed of determination, the total moisture loss of the sample is measured by changing its mass before and in the process of aging with simultaneous. by measuring the electrical resistivity: NIN of the sample layers, then the measured value is determined by the measured parameters by the forgud,, .i-U, () i: l-moisture loss of the i-ro layer ob-. where and. raztsa, t; . Yag-specific electrical resistance i-ro slo. Ohm m; -the specific electrical resistance, a layer of concrete, where evaporation of moisture is excluded. Ohm m, - total moisture loss of a ton sample (change of its mass before and during the process), G; - the number of layers of the sample.

Description

The invention relates to measuring equipment in construction, and more precisely to the methods of studying the physical properties of building materials with electric power tools, studying the processes of mass transfer and mass transfer of concrete during the aging process, and can be used in studying the properties of concrete and in building industry enterprises for working out ) technology manufacturing products from concrete. The known method of controlling the increase in the strength of cement paste of concrete, enclosed between electrodes of the same metal, by removing the electrical characteristics from the pre-polarized cement paste, which is achieved by summing a constant polarizing voltage to the controlled cement paste, 5-3.0 V for a time sufficient for polarization. After polarization, the voltage is removed and the electrodes connected to the discharge circuit determine the strength of the cement test by the average current occurring. polarizations tl. The main disadvantage of this method is that to quantify the properties of concrete, such as strength, the availability of calibration data is required, allowing cix to move from the magnitude of the polarization current, which depends on the composition of the cement paste or concrete, to the strength of the concrete. Moreover, for each set of concrete components the calibration curve varies. The closest to the present invention is a method for measuring the moisture content of materials by measuring their electrical resistance, in which the electrical resistance is measured by laying electrodes into a sample, and to eliminate the error of temperature variation, an electrical heater and temperature sensor are inserted into the material under test, then measured are the electrical resistance at two different temperatures, after which according to the obtained data, depending on the temperature coefficient For example, the desired humidity is found using the calibration curve. A disadvantage of the known method is the complexity of its implementation due to the fact that for each material studied there is a need for calibration curves (which by themselves do not have sufficient accuracy), and for concrete - them for all its varieties. The purpose of the invention is to extend, improve the accuracy and efficiency of measurements. The goal is achieved by the fact that according to the method of determining the hollow moisture loss of concrete in the process of keeping the sample in shape, including the measurement of specific electrical resistance of the layers, the total moisture loss of the sample is measured by changing its mass before and in the process of overstuffing with simultaneous measurement of the specific electrical resistance of the sample layers, then The measured values are determined using the formula gy Pi - g Po U, (I) () where is the moisture loss of the ith sample layer, g; p, is the specific electric co, resistance of the i-ro layer, Ohm-m Pp is the specific electrical resistance of the layer of concrete, where evaporation of moisture is excluded. Om-It; and - sugar moisture loss of a concrete sample (change in its mass before and during the aging process), g; n is the number of layers of the sample. The drawing shows a schematic diagram of an installation for determining the layered moisture loss of a concrete sample. Form 1 with the test specimen 2 is weighed immediately after the concrete mixture is molded and wedged together with the conditions under conditions similar to the test sample, but at. excluding moisture evaporation, a layer of concrete 4. As layer 4, for example, a specimen held in a hermetically sealed enclosure can be taken, or to simplify, a layer of the test specimen itself can be taken, located outside the zone of moisture evaporation (remote from the evaporation surface, more than 30 cm). At any particular point in time, the sample to be studied is weighed and the electrical resistivity of all its layers and layer with interrupted moisture losses is determined using an .1g.1meter 5, switch b, electrodes 7 and connects lnyh wire 8. Wire T definition fibrewise vlagopoter concrete sample with neopalublennoy upper surface and a height of 30 cm, consisting of a three layers of 10 cm each. The calculation of layered moisture losses is produced by the formula (1). According to the measurement result, the specific electrical resistances of the three oCipasua layers are equal ,. Ohm-m: first f 35.36; second -, (1; third - p 13.96. specific electrical resistance of a layer of concrete with the evaporation of moisture excluded.

31052968 "

Yao 13,08 hmm. The change in mass of the layer-by-layer moisture loss of a concrete sample

The concrete before and during the process, according to the formula (1), gives the following reductions, i.e. his sum / lag moisture:

Terry, and 128.08 g. Calculation by-for the first layer eg35.36- Cg - t3.08

1 {gyyi .. (.. ((e..o8 g;

similar, for the second U ™ 23.57 g, the absence of calibration curves, the third Ug discharge of 6.43, the increase in measurement accuracy to ± 0.5% per

This time, as the use of the proposed calibration method of calibration curves gives

Soil moisture permeability determinations are in the order of 1.5%. In the case of a concrete, a comparative method also appears to be possible with a prototype. Simplification of the procedure. The operability of measuring the moisture content of moisture content due to the loss of concrete.

Claims (1)

METHOD FOR DETERMINING LAYERED WATER LOSS OF CONCRETE in the course of curing in the mold, including measuring the electrical resistivity of the layers, characterized in that, in order to simplify, improve the accuracy and efficiency of determination, measure the total moisture loss of the sample by changing its mass before and during exposure with simultaneous .measurement of electrical resistivity; layers of the sample, then the measured value is determined by the measured parameters by the formula,. 1 'n' ΣΞ (Chrrh · r ₀ ) fourteen where U, - moisture loss i-ro layer about-. razsa, -g; . Pi - electrical resistivity of the i-ro layer, Ohm · m; Ro - electrical resistivity, concrete layer, where S and moisture evaporation is excluded. Ohm · m - total moisture loss of the concrete sample (change ω s its masses before and during the aging process), g; »E = c. η - the number of layers of the sample. ’