SU681012A1 - Method of the preparation of concrete mixes and mortars - Google Patents

Description

one

The invention relates to the technology of cement mortars and can be used in the manufacture of precast and monolithic reinforced concrete products and structures.

There is a known method for preparing cement concretes and mortars by mixing in a binder, aggregates, mixing water with the introduction of various additives 1.

There is also known a method for preparing a construction mixture, which includes mixing in a binder, aggregates, and mixing water, followed by vibroactivation of the mixture after the content of the corresponding first stage of the structure formation process 2.

The disadvantage of this method is the difficulty of carrying out, under production conditions, exposure times of 60-120 yin, the strength is not high enough and. water resistance of the resulting material.

The purpose of the invention is to increase the strength, water resistance and shorten the production cycle.

This is achieved by the fact that the method of preparing concretes and mortars, including mixing in the binder, aggregates and mixing water, with

the subsequent vibroactivation of the mixture after holding the corresponding first stage of the process of structure formation involves the preliminary mixing of the mixing water with 0.1-0.3% of the cement quantity, followed by mixing with the other components of the mixture.

When the concrete mix is mixed with water previously mixed with 0.10, 3% cement, the duration of the first stage of the process (the stage of forming a spatial framework) of the structure formation of a colloidal structure is reduced from 60-120 minutes to 1015 minutes.

Preliminary introduction of a part: cement into the mixing water plasticizes the concrete mix, significantly improving workability.

All this significantly shortens the technological cycle of concrete preparation and accelerates the subsequent hardening.

Example. Dp of concrete preparation use Zdolbunovsky cement of mark 400, sand, crushed stone and water in the following quantities per 1 m of mixture:

Cement405 kg

Sand400. Kg Rubble 1314 kg l ,. During the preparation, 0.3% (by weight of water) cement is introduced into the water, after which the resulting suspension is mixed with baking powder components. When preparing a concrete mix according to the proposed method, the amount of mixing water is reduced by 10%, cement by 10% in relation to the above amount, the workability of the concrete mix remains unchanged. A part of the samples is subjected to vibration 5 minutes after the preparation of the concrete mix, and a part of the samples 15 minutes later. The vibration is performed at a frequency of 50 Hz, amplitude, 5 mm, for 1 minute. Then the samples are subjected to heat and humidity treatment according to the 2 + 3 + 3 + 2 mode with a maximum heating temperature of 80-85 C. The test results are shown in the table.

5 15

242,250

270

5 15 290

As can be seen from the example, the introduction of optimum micro additive cement into the mixing water makes it possible to reduce the cement consumption in the concrete mix by about 10% and reduce the consumption of water while maintaining workability and, in combination with optimal vibroactivation, increase the strength of the concrete by 10-15%.

The application of this method will significantly improve the quality of the products of the structures / cemented works by increasing the strength and water resistance of the material.

At the same time, the use of this water treatment in combination with the vibroactivating concrete mix at the precast concrete plants will allow to increase the formwork turnover, reduce cement consumption when achieving the specified strength, reduce the cost of products and structures. .

WB

AT 8

Claims (2)

1. Vavzhin F. and Krchma R. Chemical additives in construction, M., stroiizdat, 1964, p.8. 2. Authors certificate of the USSR, 310877, cl. From 04 to 7/38, 1969.