RU2533506C1 - Method of activating hardening water of cement-based composites - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to methods of activating hardening water of cement-based composites. The method of activating hardening water of cement-based composites includes treating tap water in a plasmatron with low-temperature nonequilibrium plasma in a period of time ranging from 1·10^-2 s to 5·10^-2 s.

EFFECT: high efficiency and degree of activation of water in order to speed up hydration and strength gain in the early stage of concrete hardening.

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Description

The invention relates to the field of building materials, in particular the production of concrete, reinforced concrete products, mortar, cellular concrete and other building materials and products based on cement.

There is a method for producing cement stone, including the electrochemical treatment of a mixing fluid in a three-chamber direct current electrolyzer. At the same time, a 1-3% solution of calcium chloride is fed into the middle chamber of the electrolyzer, and tap water is delivered to the outer chambers. The electrochemical process is carried out at a rectified voltage of 220 V. Cement is shut with a solution from the anode or cathode chamber [1].

The disadvantages of this method include its low technology associated with the use of a mixing component of a chemical component during electrochemical treatment (1-3% CaCl solution) and the use of high voltage, which makes the use of this method energy-intensive and unsafe.

A method for producing cement mixing liquid is proposed, including electrochemical treatment of tap water in a three-chamber electrolyzer with ion-selective membranes, followed by the use of treated water; for mixing cement use treated tap water, selected from the middle, or cathode, or anode chambers, and the electrochemical treatment of water is carried out by alternating asymmetric current at a voltage of 40-50 V, a frequency of 500-600 Hz with a ratio of amplitudes of forward and reverse half-wave current equal to 1 , 6-1.7.

The disadvantages of this method should also include its low technology, the use of sophisticated equipment for the electrochemical treatment of water and the low effectiveness of the activated, according to the proposed method, water on the rate of hydration and curing in the early period of concrete hardening.

The objective of the invention is a method of activating the mixing water of cement-based composites in order to accelerate the hydration processes and build strength in the early concrete hardening period.

The goal is achieved by activating mixing water by treating it with a low-temperature nonequilibrium plasma. Tap water was used as mixing water. To activate, water was treated with a low-temperature nonequilibrium plasma in a plasmatron consisting of an internal rod electrode placed inside the external end electrode, between which a low-temperature non-equilibrium plasma region was created with the parameter E / N 15 × 10 ^-16 B · cm ² . The processing time for water activation varied from 1 · 10 ^-2 sec to 5 · 10 ^-2 sec, after which the water activated by the proposed method was used as mixing water to obtain cement based composites.

As a result of plasma-chemical processes during water treatment with low-temperature non-equilibrium plasma, the cluster structure of water is rearranged, as a result of which its activation occurs, which manifests itself when it is used as mixing water for cement-based composites. This is confirmed by the acceleration of hydration processes, characterized by acceleration of the start and end time of cement setting and acceleration of concrete strength in the early period. To obtain comparative characteristics of the increase in strength by a known method (patent RU No. 2163582, C04B 40/00) [2] and by the proposed method, concrete samples based on cement grade M500DO were obtained and tests were carried out to determine the strength in accordance with GOST 10180-90 and terms setting in accordance with GOST 310.3-76, GOST 31108-2003.

The properties are shown in table 1. According to paragraph No. 1, the test results of the start and end of setting and tensile strength on the compositions obtained by the method described in the prototype (patent RU No. 2163582) are entered.

The test results show the high efficiency of the proposed method for the activation of mixing water of cement-based composites.

Sources:

1. Auto No. 1705266, M. cl. ⁵ C04B 40/00, Bull. No. 2, 01/15/92 (analog).

2. Patent RU 2163582, C04B 40/00 (prototype).

3. GOST 310.3-76.

4. GOST 31108-2003.

5. GOST 10180-90.

Table 1 No. Mixing water Setting time, min Compressive Strength (MPa) at Age (days) Start the ending one 3 5 7 fourteen 28 one processed by the prototype at U = 50V; 1 = 0.155; S = 1.7, frequency 500 Hz 110 230 5,6 / 12 12.7 / 27 21,2 / 48 28.0 / 59.6 37.6 / 80 47.0 / 100 2 Plasma-chemically treated mixing water. Processing time 1 · 10 ^-2 sec 90 200 8.8 / 16 18.7 / 34 30.3 / 55 40.2 / 73 45.7 / 83 55.0 / 100 3 Plasma-chemically treated mixing water. Processing time 2 · 10 ^-2 sec 80 180 9.8 / 17 19.0 / 33 30.0 / 52 41.4 / 72 46/80 57.5 / 100 four Plasma-chemically treated mixing water. Processing time 3 · 10 ^-2 sec 75 180 11.4 / 19 21.0 / 35 34.3 / 57 45.0 / 75 50.5 / 84 60.1 / 100 5 Plasma-chemically treated mixing water. Processing time 5 · 10 ^-2 sec 70 170 12.3 / 21 23.5 / 40 35.2 / 60 45.8 / 78 49.9 / 85 58.7 / 100 Note: the denominator indicates the percentage of concrete strength relative to concrete strength at the age of 28 days

Claims (1)

A method of activating mixing water of cement-based composites, comprising using tap water as mixing water, characterized in that, in order to accelerate the hydration processes, the setting and strength of concrete start and end time in the early period, the mixing water is activated by low-temperature nonequilibrium plasma in the period time from 1 · 10 ^-2 sec. to 5 · 10 ^-2 sec.