1 Best thixotropic properties have. Thixotropy (rocks)

Concrete repair is often used for special purpose mortars. They are characterized by high weather resistance and are able to be used on an artificial stone operating in hard operation (facades, tunnels, parking). One of these solutions are thixotropic mixtures, characteristics and principle of the use of which will be considered below.

Mechanical loads (vibration, drums, etc.) can act on artificial stone, physical (wear, shrinkage, freezing and thawing, temperature fluctuations, salting crystallization).

Highly weaken the design chemical loads. Due to the capillary-porous structure, alkalis and sulfates, salt solutions are capable of penetrating into the thickness of the concrete and ultimately influence its carrying capacity. If the construction has not stood loads and requires repair, the choice of working composition relies on the assessment of its condition and causes of damage.

The reasons for the destruction of concrete are very diverse, but they all inevitably lead to the need to repair

Thixotropic mixtures - what is it

The thixotropic repairs for concrete is a dry mixture based on high-strength cement, mineral aggregate, modifying additives. In contrast to other cement analogues, the mixture contains reinforcing fiber.When mixed with water, the material forms a high-strength solution that does not give shrinkage. It is effective in repairing and restoring horizontal and vertical surfaces of damaged concrete structures.

Scope of application

The material is intended for professional and non-professional use.

With professional repair, thixotropic mixtures are used in the following cases:

• construction Repair and Restoration Destroyed concrete structures, including due to corrosion of reinforcement (beams, edges, columns). The elimination of defects admitted during the construction or those that arose during operation;
• repair of the protective layer, filling hard seams, elimination of surface defects (new filling seams, gravel sockets, open fittings, traces from formwork removal);
• alignment of walls, enclosing structures;
• repair baseunder strong abrasive loads, railway structures of hydraulic structures;
• waterproofing work on the roof, in the basement, concrete tanks and trays;
• pouring foundations and monolithic housekeeping, deploying prefabricated concrete structures;
• repair of floor coverings industrial structures under large mechanical loads and under the action of aggressive media;
• repair boiler rooms, CHP, chimneys, bridges, viaducts.

In the private sphere, thixotropic mixtures are used to repair concrete screeds, floors, tracks, wells, stairs, steps, basements, vegetable pits. The material is successfully used for sealing strokes, cracks, repairs of garages, concrete slabs for various purposes.

In general, the solution is effective when repairing and restoring any concrete or railway structures subject to static and dynamic loads. They work at the facilities of civil, transport construction, on hydraulic structures.

Specifications

The repair thixotropic mixture is ready to prepare a powder with a specially designed recipe. When mixed with water, it turns into a working solution with high thixotropy. This allows you to apply it on vertical surfaces without splitting without formwork. The material can be applied with a thick layer.

After curing, the composition is characterized by the specified properties:

• waterproof;
• high strength in compression and bend;
• good grip with old concrete, reinforcement;
• thermal expansion, vapor permeability, the elastic module almost fully correspond to the similar characteristics of high-quality concrete;
• resistance to abrasion.

However, thixotropic mixtures have a number of restrictions on use. They do not work on smooth surfaces (roughness should be provided), the valve is introduced if necessary. The material cannot be used for anchoring and when pouring to formwork.

The application of thixotropic mixtures is realized only at t over 5 degrees.

The disadvantages include such a property of thixotropic solutions as the need for care. The material exhibits all the stated characteristics only when applied in humidity conditions or during water spraying. This ensures that all product properties will reveal correctly. This is not easy to achieve in the construction sites.

Typical technical data

Tools, equipment and equipment for thixotropic concrete repair

To implement repair work, electric professional equipment and hand tools will be required.

At the site must be present such a kit:

• surface preparation equipment: grinding machines, grinder, construction vacuum cleaners, compressors, high pressure apparatus, sandblasting, perforators, jackhammers;
• tool: trowels, shovels, spatulas, chisels, drills with mixing nozzles, brushes, metal brushes;
• measuring instruments: to determine the strength of concrete, viscosity of working solutions, to search for fittings, thermometers;
• p / e film to protect the finished layer;
• overalls, personal protective equipment.

Preparation of the foundation

Tixotropic mixtures are most often used for concrete construction, that is, to restore its carrying capacity.

In view of this, specific requirements are presented to concrete and railway surfaces:

• strength, ability to carry a load (carrying capacity);
• lack of peeling, destroyed layers;
• lack of contamination negatively affecting adhesion (fats, oils, dirt, dust, rust, paint);
• rough texture.

All weak parts of the base are removed by flesh to solid structural concrete. Any compounds that remain from previous work are also deleted. Reinforcing rods and concrete itself are processed. Work is carried out until the elements are released from cement milk, dirt, oils, fats, paints and varnishes.

Hydraulic cleaning method is unsuitable where it is unacceptable an increase in air humidity

Methods of cleaning grounds:

• mechanical - For the fracture strip, the defects use jackhammers, perforators, kirk, pneumatic goods. Cleaning is carried out with sandblasting, shot blasting, grinding machines and high pressure apparatus. This is a universal method of preparation, which is advisable to apply in all cases, regardless of how much concrete is damaged. However, the technique does not apply where dustiness is unacceptable;
• thermal - It is implemented using special burners. On concrete, let's say not higher than 90 degrees. The thermal method is effective with a slight depth of damage - up to 5 mm. High temperature allows you to remove traces from oils, rubber, organic compounds. After such treatment, it should always be mechanical or hydraulic;
• hydraulic - Used hydraulic installations and high pressure apparatus. This is a universal solution for efficient and fast cleaning of concrete;
• chemical - Special chemical compositions are used to prepare concrete. The method can help out where it is impossible to carry out mechanical cleaning. After the tranny, the base is always washed with water.

If a defective concrete is discovered on the work area, it is required to cut off with concreterases, bumps or perforators. All loose layers with insufficient thickness, structural damage, peeling coatings are subject to removal.

Before applying a thixotropic solution, the base is saturated with water. The surface must be wet, but without puddle. If liquid clusters are detected, they are removed with a sponge or compressed air. In some cases, the working solution is applied to a low layer of primer.

Applying adhesive soil

The material is also applied to the moistened base. If concrete absorbs moisture well, moisturizing is being implemented repeatedly. A competently prepared surface should be wet, but without brilliance.

Principle of application:

• the soil is distributed by wet treading or medium hard brushes;
• when working controls the filling of pores and irregularities of the base;
• the thixotropic repair is applied to the unexpressed primer. But, if the surface managed to dry, realize another fresh layer of soil.

If corrosion reinforcement is required

In accordance with GOST 31384-2008, GOST 32016-2012 it is necessary to provide long-term anti-corrosion and passivation (inactivity) of steel reinforcement. At the first stage of protection, the reinforcement rods are cleaned. According to GOST Rio 8501-1-2014, the newly installed or old valve must be cleaned to the degree of SA 2 ½. Works are carried out by hand or metal brushes. A mechanized method can be used by sandblasting machines.

Ideally, the depth of the box should exceed the width of the seam 3-4 times

If there is a damaged concrete on the work site, it is removed along with the reinforcement rod. The use of perforators and jackhammers is unacceptable, as this may entail a decrease in adhesion of concrete and reinforcement. Opened reinforcement rods are completely taken away. The gap between steel and concrete should be at least 20 mm. If the diameter of the rods is small (up to 5 mm), let's say a smaller clearance by 10 mm.

Application:

• an anti-corrosion composition is applied to the purified fittings in two approaches. When working, use the brush of the average rigidity or the teterkening technique (wet). The thickness of the first layer should be 1 mm. When the first layer begins to be captured, the second identical thickness immediately realizes;
• the edges, the transition zones of the concrete fittings, the fastening of the wire take place especially careful processing;
• if the first layer managed to completely grab up to apply the second, one more fresh layer is satisfied.

Elimination of active leaks

At this stage there is a task for waterproofing the design and eliminating active leaks. If pressure leschs are detected on the surface, they are eliminated by hydroplates (rapidly frustrating waterproofing compositions). Such materials are capable of solving under pressure fluid for 1 min.

It requires additional surface preparation:

• sections of active leaks are expanded. When working, an expansion of the gap is provided inside the design to a depth of at least 3 cm, 2 cm wide. The cavity is washed with water;
• the base is cleaning with sandblasting or high pressure apparatus.

In the liquidation of the leaks on the basis of the rapid-hardening mixture, hydrophombal is formed. The material must take the shape of a truncated cone or ball. After that, it with force is pressed into the zone of active leakage for 3-5 minutes. If the waterproofing section is large, they work with it in several techniques.

If flowing is characterized by a large intensity, a drainage polyethylene tube is inserted into the repaired area, which will allow localize the removal of water. The zone around the pipe is treated with hydrophomboba. When the material hardened, the tube is removed, batching the hole by quick-crumbling composition.

Application of thixotropic solution

If the surface is well prepared, characterized by a rough texture, and does not require primer, it is pre-moistened. In all other cases, the spectrum of operations discussed above is carried out. In any case, before applying the main solution, concrete must be wet, but without shine.

The thickness of the applied solution can vary from 6 to 35 mm

Proper solution:

• the required number of bags is revealed immediately before mixing;
• a small amount of water is poured into the mixer. 25 kg of dry mixture requires 3.9-4.0 l of water;
• the equipment turns on, after which the dry powder continuously falls asleep into the mixer;
• the composition is mixed 1-2 minutes until it becomes homogeneous;
• if required, a small amount of water is added, the solution is re-stirred for 2-3 minutes;
• to reduce the risk of shrinking deformations, when mixing, it is recommended to apply a moisture-holding additive;
• to mix a small amount of solution, it is not allowed to apply a concrete mixer, but a clean container and a drill with a paddle nozzle. With this method, stirring is realized 5-6 minutes;
• the viability of the solution, regardless of the preparation techniques is 60 minutes. To prepare 1 m3 of the working mixture, 1800 kg of dry thixotropic powder will be required.

The need for water in the water is indicated in the table.

Manufacturing jobs

The solution is spreading on horizontal and vertical surfaces by manually by means of a spatula, cell or trowel or by a wet treading technique. At the same time, the layer is aligned.

If the conditions of work are such that it is required to implement a layer of over 35 mm in thickness, the thixotropic solution is applied in two approaches. The second and all subsequent layers are implemented when the previous grabbed, but did not harde it to the end.

When applying a layer, a thickness of over 50 mm, reinforcement is necessary.

The grid is installed like this:

• the gap between the reinforcement and the base should be 10 mm;
• the thickness of the protective layer above the grid can not be below 10 mm.

If a mechanized method (spray) is used, use special equipment. After completing the work and equipment, and the tool is washed with water.

Caring for the surface

When work on thixotropic repair is completed, the surfaces must be protected from the premature moisture loss for 24 hours. If the weather is dry and windy, the protection time is extended to two days.

Care is implemented in several ways:

• on the renovated base water is sprayed;
• the surface is covered with a wet burlap or polyethylene film;
• a film-forming composition is applied to concrete.

Quality control

Control is implemented by external inspection

After three days after the repair, the quality of work performed is checked. On the surface there should be no visible peeling and cracks. If such defects are detected, this indicates errors in the use of material. It is necessary to re-repair work.

If a deeper check is required, the method of assessing the strength of adhesion, compressive strength, also determines the brand of waterproof concrete.

Safety technique

Dry thixotropic compositions contain cement. The material may cause irritation of mucous membranes and skin. It is necessary to avoid mixing the mixture into the eyes and contact with the skin. If this happened, the affected areas are thoroughly washed with water, then refer to the doctor.

Persons are allowed not under the age of 18. All staff must pass a medical examination, training, instruction on TB. If it is planned to conduct work at height, staircases and scaffolding apply.

Cost of concrete thixotropic repair

Thixotropic mixtures offer manufacturers such as BASF, MAPEI. The average cost of the bag, weighing 30 kg begins from 1.9 thousand rubles. The cost of repair of concrete begins from 2.5 thousand rubles per m3.

findings

Modern thixotropic mixtures can be confidently used to repair and align concrete structures. The material is convenient in operation, presented at an affordable cost, it is easy to apply even to vertical surfaces. The only restriction with which you can face - production of work is possible at temperatures above +5 degrees. If you need to eliminate the defect in winter, it is better to refer to the polymer compositions.

Details of concrete repaid thixotropic makeup ProfsRin are shown in video:

Thixotropy.

Thixotropy.

The ability of some dispersed systems is reversibly diluted with sufficiently intensive mechanical. The impacts (stirring, shaking) and harden (lose) when staying alone. T.- The characteristic property of coagulats. The structures, which can be destroyed by an unlimited number of times, and each time their properties are completely restored. Examples of typical thixotropic structures can serve as systems formed by coagulation of aqueous colloidal dispersions of iron hydroxide, aluminum hydroxide, pentoxide vanadium, bentonite suspensions, kaolin.

Mechanical The properties of thixotropic structures are characterized by the values \u200b\u200bof three parameters (P. A. Rebelder): the greatest eff. Viscosity H 0 of a practically non-destructive structure, the smallest eff. Viscosity H. M. extremely destroyed structure and limit shift voltage P. 0 . Dependence Eff. Viscosity H from the applied shift voltage P. can be described by ur

For small values P.not disturbing peace or causing a very slow flow, the structure has the properties of a solid body, since its reduction under these conditions exceeds the rate of destruction. For R>> R 0 The system turns out to be extremely destroyed and is a small viscosity H M.. Value P. 0 characterizes a non-destructive structure. The process of restoring the destroyed structure in peace can be characterized by increasing time strength.

In some cases, the application is small P. and deformation with low speed accelerate the increase in strength and structuring of dispersed systems; This is the phenomenon of Naz. R e o p e to s and e. Sometimes concentrated dispersed systems (pastes) are detected by the increase in H with an increase in the deformation rate, accompanied by a certain increase in the volume occupied by the system: when deformed solid particles form a more loose frame and the existing liquid medium turns out to be Not enough to provide the system.

T. Dispersed systems has great practical. value. Consistency lubricants, paint materials, ceramic should be posted with thixotropic properties. Mass, washing, used during drilling wells, MN. Food products. I. H. Vlodais.

Physical encyclopedia. In 5 volumes. - M.: Soviet Encyclopedia. Editor-in-Chief A. M. Prokhorov. 1988 .

Watch what is "thixotropy" in other dictionaries:

Thixotropy ... Orphographic Dictionary

Thixotropy. - - the ability of dispersed systems to restore the original structure destroyed by mechanical effects. [Terminological dictionary on concrete and reinforced concrete. FSUE "NITS" Construction "NIIZHB and M. A. A. Govnieva, Moscow, 2007 110 p.] ... Encyclopedia Terms, Definitions and Explanations of Building Materials

- (from Greek. Thixis Touching and Trope Rotate Change), the ability of dispersed systems to restore the original structure destroyed by mechanical effects. Thixotropy Important technological property of flushing liquids used at ... Big Encyclopedic Dictionary

SUT., Number of synonyms: 1 thixotropy (1) Dictionary of Synonyms ASIS. V.N. Trishin. 2013 ... Synonym dictionary

The ability (property) of some students and gels (gelatin, agar agar, iron hydrates) in mechanical exposure (shaking, stirring) is disseminated and moved into the evils that are spacious again. These ... ... Geological Encyclopedia

thixotropy. - The phenomenon of the reversible process of the transition of students and gels into a liquid state with mechanical exposure to the subject of the oil and gas industry EN Thixotropy ... Technical translator directory

thixotropy. - - the ability to spontaneously restore the structure of gelling systems after their mechanical destruction. General Chemistry: Textbook / A. V. Zhulkhan ... Chemical terms

- (from Greek. Thíxis Touch and Tropē turn, change), the ability of dispersed systems to restore the initial structure destroyed by mechanical effects. Thixotropy Important technological property of washing liquids used ... encyclopedic Dictionary

thixotropy. - Thixotropy thixotropy reversible change in the physicomechanical properties of polymer and dispersed systems in mechanical exposure in isothermal conditions. For liquid media, it is manifested in lowering viscosity during the flow and gradual ... ... ... Explanatory English-Russian dictionary on nanotechnology. - M.

It is necessary to transfer the contents of the article by the thixotropic fluid to this article and put redirection from there. You can help the project by combining articles (CM. Instructions for combining). If necessary, discussion of expediency ... ... Wikipedia

(from Greek. Thixis - touch and trope - turn, change * thixotropy of rocks; n. Thixotropie der Gesteine; f. Thixotropie des Roches; and. Capacidad Tixotropica de Rocas, TIXTROPIA de Rocas) - Physico-chemical phenomenon In some colloidal dispersed systems, for example, in coherent rocks, and consisting in their spontaneous discharge under the influence of mechanical impact (shaking, stirring, vibration, ultrasound, etc.) and the subsequent restoration of the structure while eliminating these effects. Thixotropy is explained by the reversible structural links between the mineral particles of the coherent breed. With a certain mechanical exposure, there is a transition of associated and immobilized water into the free, which leads to a decrease in the strength of structural bonds and the dilution of the rock. The cessation of exposure leads to the reverse transition of water from free into the associated condition and strengthening rock (thixotropic hardening).

An indicator characterizing the tendency of rocks to thixotropic softening is pura. It is customary to measure the average radius of the base of the cylindrical sample (mm) after its vibration at a frequency of 67 Hz and amplitude of 1 mm. The initial radius of the sample is 8 mm, and the height of the cylinder is 20 mm. The magnitude of the indicator of the ziyobility varies from 8-9 for noncuserotropic rocks up to 15 or more for high-balanceotropic rocks. A more general indicator is the limit of structural strength under dynamic exposure, defined as an extreme alternate acceleration, in which the strength of the rock is not reduced. It is measured in m / s 2. Thickotropic hardening is characterized by the recovery time (C), during which the maximum strength of the breed is achieved during recovery.

Thixotropy is determined by the qualitative and quantitative composition of their dispersed phase, the particle form and their hydrophilicity, composition and concentration of pore moisture, etc. The basic effect has a granulometric composition of the rock. Thickotropic phenomena are characteristic of rocks with the content of clay particles of at least 1.5-2%.

Thixotropy is widespread in nature and has both negative and positive effect on technological processes in the development of wet connected rocks. For example, when transporting such rocks, thixotropic discharge causes their intensive adhesion to the working surfaces of the transport equipment, reducing its capacity by 1.5 times. On the other hand, thixotropy is used when drilling drilling work, piles. Thixotropy - the cause of landslide phenomena.

Thickotropy is a concept, maybe not widely known, but encountered everywhere. Paintwork materials, printed inks, plastic lubricants for bearings, many food products - all these substances have certain viscosity properties that change over time. An option may be two: either the substance begins to flow, that is, the viscosity decreases, or to stick - the viscosity increases. The first phenomenon is called thixotropy, the second - reopexia. Thixotropy is characteristic of polymer and dispersed systems in mechanical exposure in isothermal conditions. Signally speaking, this is the ability of a substance to restore its yield strength after stopping the impact (shaking, stirring, vibration, etc.). The phenomenon of thixotropy is due to the possibility of reversible changes inside the material structure, for example, in the destruction of the supramolecular structure in polymers or coagulation of colloid particles inside the dispersed system.

What are the thixotropic properties

Thickotropic properties are determined by the qualitative and quantitative composition of the dispersed phase of the substance (in the plastic lubricant - the thickener) and are characterized by the values \u200b\u200bof three parameters: the greatest effective viscosity, the smallest efficient viscosity and limit shift voltage.

The thixotropy of colloidal systems is of great importance and is widely used in industry, in production and in everyday life. So thixotropic properties are more or less consistent lubricants, paint, washing solutions for drilling wells, many food products.

Thickotropy does not need to be confused with the concept of pseudoplasty. Pseudoplastic substances lose their viscosity during the temporary shift voltage, thixotropic - experience the impact constantly and lose viscosity properties over time.

Plastic lubricant for bearings and its thixotropic properties

Plastic grease for bearings is one example of a dispersed system, characterized by high thixotropic properties, which, together with the viscosity parameters and shift strength, determine the rheological properties of greases. Riology - Science of the flow, studies the ability of liquid and plastic materials to flow and deform. The fact that plastic lubricants can change their structure reversibly is determining to use them in vertical and inclined nodes of friction without loss. After all, if the bearing is lubricated with liquid oil, it is necessary to constantly monitor its number: it can flow, evaporate and requires frequent application. Plastic lubrication fills the bearing cavity, seals the node and prevents the penetration into the bearing of abrasive particles, which can lead to a mechanism. Thickotropic properties provide a stable protective film between working surfaces, which softens blows from vibration and reduces the effects of wear from the friction of sliding.

Plastic grease for bearings is used in more than 90% of rolling bearings. When greased a lubricant in the cavity of the part running on high revs, you need to comply with the necessary proportions. Bearings with frequency of rotation up to 1500 rpm are filled with 2/3, over 1500 rpm - per 1/3 of free volume. If the surplus is visible, they need to be removed.

Thixotropy. (thixotropy) (from Greek. θίξις - Touch I. τροπή - Change) - the ability of the substance to reduce the viscosity (diluted) from mechanical impact and increase the viscosity (thicken) at rest.

Thixotropic liquids

Thickotropia should not be confused with pseudoplasty. In pseudoplastic fluids viscosity decreases with increasing shift voltageWhile in thixotropic fluids viscosity decreases with time with constant shift voltage.

Thixotropic fluids are fluids in which at a constant deformation rate, the shear voltage decreases in time.

The viscosity of some liquids under constant ambient conditions and shift rates varies with time. If the viscosity of the fluid is reduced over time, the liquid is called thixotropic, if it increases - reopec.

Both behaviors may occur both with the above-described types of fluids, and only at certain shift speeds. The time interval can vary greatly for different substances: some materials achieve a constant value in seconds, others in a few days. Reopecable materials are quite rare, in contrast to thixotropic, which include lubricants, viscous prints, paints.