RU2667367C1 - Method of producing concrete mixture with utilization of previously produced residues thereof - Google Patents

Abstract

FIELD: construction.SUBSTANCE: invention relates to the field of construction, in particular to methods for preparing mixtures containing astringent components, for example concrete. Method for producing a concrete mixture with the utilization of the previously produced residues of this mixture comprises the following steps: in the tank with recyclable residues of the concrete mixture, the composition of which is known, load the amount of inert components included in the composition of the recycled residues of the concrete mixture specified by the process control system, and the walls of the tank are cleaned of the recyclable residues of the concrete mixture by mechanical action, thus obtaining a mixture of inert components with recyclable residues of the concrete mixture; resulting mixture is loaded into the mixer, releasing the reservoir, weighed the mass of this mixture in the mixer and stores the obtained data in the process control system; after dry cleaning of the tank walls, the amount of water set by the process control system is poured into the freed tank to further remove the recycled concrete mixture remaining in the tank from the tank walls; resulting mixture is charged to a mixer; reweighting is carried out, which allows to determine the total weight of the loaded mixture after dry cleaning together with the mixture after wet cleaning, and storing the obtained data in the process control system; process control system based on the obtained data of the results of weighing the mixer in the preliminary stages and information on the loaded amount and composition of the inert components and water determines the number of necessary components for the production of a concrete mixture with a specific composition of components required for loading into the mixer; additional components in the required quantity are loaded into the mixer and mixed to produce a concrete mixture.EFFECT: invention simplifies the technological cycle of recycling the remains of a concrete mixture.1 cl, 2 dwg, 4 tbl

Description

The field of technology.

The invention relates to the field of construction, in particular to methods for preparing mixtures containing cementitious components, such as concrete.

The level of technology.

A known method of recycling industrial waste in the production, delivery and laying of concrete, and installation for implementing the method (German patent application DE4431632, B01D21 / 32; B03B13 / 00; B03B9 / 06, published 07.03.1996). This technical solution is intended and can be used for the extraction and reuse of residues, in particular concrete. When implementing the method, separation is carried out into the coarse fraction and the residual fraction, while the residual fraction is returned to production. The density and mass of the residual fraction is measured before returning to the mixing plant, where the solid material is re-produced. Also declared installation with the ability to measure the residual fraction in the feed channel when fed to the mixing station. The radiometric unit provides non-contact measurement of sediment density. The mass measuring device controls the mass of the residual fraction by means of a balance or a flow meter. This technical solution describes a method implemented within the framework of a specialized enterprise, which is expensive to implement and cannot be applied in a confined space.

A mobile device for processing residual concrete mix is known (patent for utility model CN203185500, B01D36 / 04; B28C9 / 00, published on September 11, 2013). This technical solution discloses a mobile device for the disposal of residual concrete mix. The device comprises a chute for supplying water for washing the vehicle, a sand and stone separation unit, a hydrocyclone separation system, a mixing box, a piping system, a filter extraction system and an automatic control unit. The sand and stone separation unit includes a concrete mix separator, a screen for separating sand and stone; and the hydrocyclone separation system comprises a hydrocyclone separator with a trough. Compared with the prior art, a mobile device for processing residual concrete mix allows reuse of the concrete mix, and has the advantage that the mixer is made in the form of a mixing box, which eliminates additional cleaning of the mixer when using this device, so the device is more convenient in operation; the vibration motor is mounted on a frame with a trough for unloading material from the washed vehicles, so that the material is fed more smoothly. The disadvantage of this device is the large amount of contaminated water, the purification of which for subsequent use is a complex and expensive process.

A known system and method for the reuse of sludge water and other waste in the production of concrete mixtures (patent CN102320082, B28C9 / 02, publ. 18.01.2012). The system includes a mixer and a transportation system, flushing equipment for washing concrete waste from mixtures, a pump system, equipment for separating washed sand from washed concrete, a contaminated water tank for its subsequent treatment, monitoring equipment that monitors the level of solid particles in the treated water and fan pump for pumping purified water into the mixer. Since water for washing waste from the concrete mixes of the mixer, transportation system, and pumping system is completely cleaned and reused, this saves the company's resources, provides economic benefits, solves the pollution problem from concrete production, and ensures a more environmentally friendly production. The disadvantage of this system is the large amount of contaminated water, the purification of which for subsequent use is a complex and expensive process.

As the closest analogue of the claimed invention, a method is selected in accordance with the one set forth in patent CN102320082.

SUMMARY OF THE INVENTION

The objective of the invention is to provide an effective method for producing a concrete mixture with the disposal of previously obtained residues of this mixture, which allows you to save the strength and binding characteristics of concrete, significantly reducing the amount of production residues and waste. An additional objective of the present method is the ability to provide concrete mix in the conditions of construction production.

The technical result of the claimed invention is to simplify the process cycle of the disposal of concrete residues by eliminating the operations of extraction and processing of inert components, the use of cement, water and chemical additives contained in the concrete residues, as intended.

The claimed technical result is achieved due to the fact that in order to obtain a concrete mixture, utilizing the previously obtained residues of this mixture, a quantity of inert components specified by the process control system (crushed stone and sand of the corresponding fractions included in composition of recyclable residues) by which mechanical cleaning of the walls of the tank, hereinafter referred to as “dry cleaning”, of recyclable concrete mix remains is performed By mechanical action, the resulting mixture of inert components with recyclable concrete mixture, hereinafter referred to as the “mixture after dry cleaning”, is loaded into the mixer, in which the resulting mixture is weighed after dry cleaning, and the obtained data is input into the process control system.

After dry cleaning the walls of the tank and loading the resulting mixture after dry cleaning into the mixer, the amount of water specified by the process control system is added to the tank to further clean the walls of the tank, hereinafter referred to as “wet cleaning”, from recyclable concrete mixture, the resulting mixture of water and recyclable concrete the mixture, hereinafter referred to as the “mixture after wet cleaning”, is loaded into the mixer, in which the resulting mixture is re-weighed after dry cleaning together with the mixture according to le wet cleaning, and the resulting data is inputted to the process control system. The process control system, based on the obtained data of weighing results at the previous stages and information on the loaded amount and composition of inert materials and water, determines the number of necessary components for the production of concrete mix with the specific composition of components required for loading into the mixer.

Distinctive features of the claimed method for producing concrete mix is that the process of cleaning the tanks is divided into two stages: at the first stage, the cleaning is carried out mechanically and is carried out without using water by loading inert components, and at the second stage with the addition of a small volume of water. The amount of inert components loaded, their type and fractions, as well as the volume of water and the chemical additives used, are determined in advance based on the composition of the concrete mixture stored in the process control system, as well as on the basis of the volume of the tank. Thus, it is not necessary to separate the residual concrete mixture into fractions during the disposal process, which simplifies the technological cycle of their disposal for reuse.

The use of data on the initial composition of the concrete mixture, as well as the quantitative composition of the resulting mass, determined by weighing, allows you to accurately calculate the number of components required to obtain a new portion of the concrete mixture, which increases the efficiency of use of all components, in particular cement, water and chemical additives.

All operations of the method are carried out directly at the construction site, which reduces transport costs. The technological process eliminates the use of contaminated water, usually obtained with a wet cleaning method, which improves the quality of the resulting concrete mixture, and also improves the environmental performance of the process.

A brief description of the drawings.

The drawings of the application are presented in a form sufficient to understand the essence of the invention by specialists in this field of technology, and in no way limit the scope of protection of the invention. In the drawings, the same elements have the same reference numbers.

It should be understood that the drawings show those operations that require explanation, but the individual operations of the proposed method are understandable to a specialist, and they do not require additional graphical schemes.

In FIG. 1 shows a method for loading components of a concrete mixture and a method for unloading the resulting mixture at a construction site.

In FIG. 2 shows a method for loading components of a concrete mixture and a method for unloading the resulting mixture in a factory.

Examples of the method

An embodiment of the method depends on the conditions under which it is applied.

As an example of the implementation of the proposed method in accordance with FIG. 1, a method for producing concrete mixture at a construction site with the disposal of previously obtained residues of this mixture that remain on the walls of the tanks (for example, concrete mixer) will be considered and will not be further used in the production of high-quality concrete mix.

This technology allows you to utilize the remains of concrete mixture from the tank for the production of concrete mixture corresponding to a given composition, providing the same strength and adhesive properties, making it possible to use such a mixture as a bonding layer between the main concrete fillings. A similar process provides a single structural integrity of the concrete structure.

Upon receipt of the concrete mixture from the factory and its application as intended, the tank containing the mixture is cleaned directly at the construction site. The amount of inert components pre-calculated using the program of the process control system is loaded into the tank, determined on the basis of the concrete mix recipe stored in the control system. Dosing of inert components used for cleaning is done by a dispenser system. The loading of inert components for cleaning the concrete mixer can be done in different ways: by a conveyor belt, skip elevator, gravity gravity, etc. One of the special cases of loading inert components for concrete mixer for cleaning may be a situation when the concrete mixer arrives at the construction site with a trailer, in which there is crushed stone and sand in an amount sufficient to clean. After loading the inert components into the tank, the dry cleaning of its walls from recyclable concrete residues begins by mechanical action of the loaded inert components on the recyclable concrete mix on the walls of the tank, thus obtaining the mixture after dry cleaning. Inert components also partially beat off previously hardened concrete mixture, which allows partial cleaning of the tank from older layers of the mixture. In turn, the amount of such cleaning waste can be neglected, since they do not have any effect on the quality of the mixture, due to its low percentage of <1%.

The dry cleaning time of the tank depends on its design, concrete grade for workability and type of aggregate.

Volume (capacity) of concrete mixer by loading (liters) Minimum dry cleaning time (seconds) In forced-action mixers, regardless of brand, workability, depending on W / C (water-cement ratio) In concrete mixers and gravity mixers depending on the brand for workability Up to 0.3 0.3-0.4 From 0.4 Zh1 / P1 P2 P3-P5 up to 750 (inclusive) 80 60 fifty 90 75 60 from 750 to 1500 one hundred 70 fifty 120 105 90 over 1500 120 80 fifty 150 135 120

The minimum duration of dry cleaning (in seconds) from lightweight concrete mixes on porous aggregates in forced-action concrete mixers:

Volume (capacity) of concrete mixer by loading (liters) Depending on the average density of concrete, kg / m ³ Up to 1000 1000-1400 1400-1600 From 1600 up to 750 (inclusive) 180 150 120 105 from 750 to 1500 210 180 150 120 over 1500 240 210 180 135

The table shows the data for the concrete mix grade P1. Change in the duration of cleaning from concrete mixtures of other brands (in seconds):

For stiff mixtures: Ж1 +15, Ж2 +30, Ж3 +45, Ж4 +60, Ж5 +75 (increase in time).

For mobile mixtures: P2 -15, P3 -30, P4 -45, P5 –60 (decrease in time).

For liquid mixtures: P1 +5, P2 +10, P3 +15, P4 +20 (increase the duration of mixing).

After dry cleaning is performed by mechanical action, the resulting mixture after dry cleaning is loaded into a mixer, in which the resulting mixture is weighed after dry cleaning, with data stored in the process control system. Loading of the mixture after dry cleaning from the concrete mixer into the mixer can also be carried out in different ways: by gravity, by a conveyor belt, etc.

Next, the amount of water (or a solution of water with chemical additives, if there are chemical additives in the original concrete mixture) is poured into the tank by the process control system for wet cleaning, which allows additional removal of the utilized concrete mixture remaining in the tank from the walls of the tank. Water for cleaning can be taken from the tank of a concrete mixer or from any other source available at the construction site. The resulting mixture after wet cleaning, namely, a mixture of water with recyclable concrete mixture, is loaded into the mixer, in which the resulting mixture is re-weighed after dry cleaning together with the mixture after wet cleaning, and the results are stored in the process control system.

Further, the process control system, based on the data obtained by weighing the mixture after dry cleaning together with the mixture after wet cleaning, as well as information on the loaded amount and composition of inert components and water, makes calculations to determine the required amount of cement, inert components, water and , if necessary, chemical additives to obtain a concrete mixture of the initial composition. After that, dosing occurs, followed by loading of cement, inert components, water and, if necessary, chemical additives into the mixer, in which all components are mixed to produce concrete mix.

As an example of the implementation of the proposed method in accordance with FIG. 2, a method for producing concrete mixture at a plant with utilization of previously obtained residues of this mixture that remain on the walls of the tanks (for example, in a concrete mixer) and will not be further used in the production of high-quality concrete mixture will be considered.

This technology allows you to utilize the remains of concrete mixture from the tank for the production of concrete mixture corresponding to a given composition, providing the same strength and binding properties, reduces the amount of waste, thereby ensuring more environmentally friendly production.

After the concrete mixture is unloaded from the tank, the quantity of inert components previously measured using the program of the process control system is determined on the basis of the concrete mix recipe stored in the process control system. The inert components used for cleaning are dosed by the factory dosing system. After loading the inert components into the tank, the dry cleaning of its walls from recyclable concrete residues begins by mechanical action of the loaded inert components on the recyclable concrete mix on the walls of the tank, thus obtaining the mixture after dry cleaning. Inert components also partially beat off previously hardened concrete mixture, which allows partial cleaning of the tank from older layers of the mixture. In turn, the amount of such cleaning waste can be neglected, since they do not have any effect on the quality of the mixture, due to its low percentage of <1%.

After the dry cleaning is done, the resulting mixture after dry cleaning is loaded from the tank into an additional mixer, in which the resulting mixture is weighed after dry cleaning, with the data stored in the process control system.

Next, the amount of water (or a solution of water with chemical additives, in the case of chemical additives in the original concrete) is poured into the tank specified by the process control system to carry out wet cleaning, which allows additional removal of the utilized concrete mix remaining in the tank from the walls of the tank. The resulting mixture after wet cleaning, namely, a mixture of water with recyclable concrete mixture, is loaded into the mixer, in which the resulting mixture is re-weighed after dry cleaning together with the mixture after wet cleaning, and the results are stored in the process control system.

Next, the process control system, based on the data obtained by weighing the mixture after dry cleaning together with the mixture after wet cleaning, loaded from the tank after cleaning, as well as information on the loaded amount and composition of inert components and water, makes calculations to determine the required amount of cement , inert components, water and, if necessary, chemical additives to obtain a concrete mixture of the initial composition. After that, dosing occurs, followed by loading cement, inert components, water and, if necessary, chemical additives into an additional mixer, in which all components are mixed to produce concrete mix.

The technology proposed in the application has a number of features. Below is a table showing the percentage of inert components used to clean the tanks from the maximum possible number of inert components loaded during normal operation for different tanks and various gravel fractions. The cases presented are the most widespread, but others are possible.

40-70 mm 20-40 mm 5-20 mm Concrete truck
(mixer) fifteen% fourteen% 13% Gravitational
mixer fifteen% fourteen% 13% Bowl mixer 13% 12% 10% Dish mixer with activator 13% 12% 10% Planetary
mixer 13% 12% 10% Single shaft
mixer 9% 8% 7% Twin shaft
mixer 9% 8% 7%

Based on practical experience, the regularity of the possibility of using different amounts of water for the second stage of cleaning the tank, in the presence or absence of chemical additives in the composition of the original concrete, is revealed.

Type of chemical
additives Impact on tank cleaning quality The ability to reduce the amount of water. Impact on technology Superplasticizers Improvement twenty % Retarders Improvement 10% Setting accelerators Worsening Add after cleaning the tank to the auxiliary mixer Stabilizers Improvement 5% Water retention additives Improvement 3%

In addition, there are chemical additives that do not affect the quality of cleaning the tank, namely antifreeze, air entraining, regulating density and porosity, water repellent, anticorrosive, deformation regulating additives, anti-radiation, increasing electrical conductivity, bactericidal.

In the case of the use of complex additives with a multifunctional effect, the effect of the presence of additives on the degree of reduction in the amount of water used for wet cleaning of the tank depends on the complex effect of combining a specific composition and can be further evaluated in a practical way.

The use of this technology significantly simplifies the process of recycling concrete residues due to the fact that it is not necessary to separate inert components (gravel and sand) into fractions, and also allows the recycling process to be carried out without the use of special production facilities. Due to this technology, the efficiency of using water, cement and chemical additives in the concrete mixture is increased. Transportation costs associated with the delivery of concrete residues to a stationary disposal facility are also excluded. The quality of the concrete produced is significantly increased, since the need to use contaminated water in the production of concrete mix from recycling components is eliminated. It also improves the quality of work during monolithic construction, since in this case it is necessary to ensure the continuity of the supply of a new portion of moving concrete before the concrete previously laid in the formwork hardens. When using this method, the time from concrete production to laying it in the formwork is reduced. Between the main layers of concrete, a bonding layer of fresh concrete is laid, which will ensure continuity of concreting.

Claims (8)

1. A method of obtaining a concrete mixture with the disposal of previously obtained residues of this mixture, in accordance with which the following steps are performed: a) in the tank with the recyclable concrete mixture, the composition of which is known, load the amount of inert components specified by the process control system that are part of the recyclable concrete mixture, and perform mechanical cleaning of the walls of the tank, hereinafter referred to as "dry cleaning", from the recyclable concrete mixture by mechanical action of the loaded inert components on the utilized residues of the concrete mixture on the walls of the tank, thus obtaining a mixture of inert components with the utilized with the residual concrete mixture, hereinafter referred to as “the mixture after dry cleaning”; b) the resulting mixture after dry cleaning is loaded into the mixer, freeing the tank, the mass of this mixture loaded into the mixer is weighed after dry cleaning and the obtained data is stored in the process control system; c) after dry cleaning of the walls of the tank, the amount of water specified by the process control system is poured into the vacated tank to further remove the recycled concrete mix remaining in the tank from the walls of the tank, hereinafter referred to as “wet cleaning”; d) the resulting mixture, hereinafter referred to as “the mixture after wet cleaning”, is loaded into the mixer, and re-weighted, determining the total weight of the loaded mixture after dry cleaning together with the mixture after wet cleaning, and save the data in the process control system; e) the process control system, on the basis of the data obtained from the weighing results of the mixer at stages “b” and “d”, as well as information about the loaded amount and composition of inert components and water, determines the number of necessary components for the production of concrete mix with the specific composition of components required for loading into the mixer; e) additional components in the required amount are loaded into the mixer and mix them to obtain a concrete mixture. 2. A method of producing a concrete mixture using the previously obtained residues of this mixture according to claim 1, according to which, at step “c”, chemical additives present in the concrete mixture are added to the water.

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