Each modern enterprise for achievement of high results of production activity aspires to use new technologies and modern scientific developments. The Russian JSC "tsentrodorstroy" widely introduces the most interesting proposals of the leading industry and educational institutions into the practice of road construction. All enterprises of JSC "tsentrodorstroy" are busy all year round despite the seasonality of road construction. Thus, to ensure the continuity of production processes, 90% of the work on the construction of the roadbed is carried out in the winter.
In our time, nanotechnology has been widely used in road construction, including road sealants.There is a wide variety of road sealants, some of them we will consider in more detail.
Basic properties of nanomaterials
The properties of nanomaterials are determined by the nature of the initial molecules, the size of the nanoparticles (degree of dispersion) and the dispersion medium. The concept of "dispersion" is inseparable from the dispersion medium: any dispersion is carried out in any medium and any dispersed system consists of at least two phases-the dispersed phase and the dispersion medium. For all colloidal and other Microsystems, the particle – medium interaction energy is at the level of van der Waals forces or weak chemical bonds.
Nanoparticles dispersed in the gas phase (in an argon or methane matrix, in a hydrocarbon), in a matrix of another metal, in a polymer or in zeolite cavities will have different properties. There are two main reasons for these differences. First, many properties are collective and are determined not by a single particle, but by their ensemble distributed in the dispersion medium. Secondly, the surface atoms of the particles interact with the dispersion medium, and the energy of this interaction is at the level of the energies of chemical bonds. If the medium uniformly surrounds the particle on all sides, its action on the particle is isotropic. The influence of the environment can be highly asymmetric. This situation is realized when the nanoparticle is on the surface of a solid body, for example, on the smooth surface of single crystals or highly developed surface of catalytic carriers. This cannot but affect the structure and properties of the particle.
A well-organized surface of a single crystal has a structuring effect on the nanoparticle growing on it (replication effect). Often the first two layers of atoms directly adjacent to the surface repeat its structure, while the shape of the nanoparticle on the surface changes, most often it becomes non-spherical. A distinctive feature of nanoparticles is a limitation in size or in the number N atoms in the particle. This limitation is determined primarily by the ratio of the number of surface and internal atoms. For nanoparticles, the fraction of surface atoms is commensurate (or even greater) with the number of atoms in the particle volume. The boundary between nanoparticles and classical dispersed systems is illustrated in Fig.1 Regularities of property changes within nanoparticles are fundamentally different than for larger particles. If we consider the whole set of properties of metal-containing particles, then for an arbitrary particle containing N > 103 atoms, this set of properties does not differ from the properties of a compact metal.
The energy of nanoparticles is such that they are able to interact effectively with any chemical compounds, including inert gases. In this sense, it is true that for nanoparticles, such as metal, there is no inert medium. The depth of interaction with the medium is determined by two main factors: the particle size (respectively, the proportion of surface energy in the total energy of the particle) and the nature of the metal (atomization energy, electron work function, ionization potential). O2, CO, CO2, H2O, ethylene, hydrocarbons effectively interact with nanoparticles, which are sorbed and react with the surface of nanoparticles. Thus, there is always a shell of light atoms or molecules on the surface of a nanoparticle.
Nanocomponents in the structure of the sealant
In construction, nanotechnology is understood as the use of nano-additives and nanoprimes, that is, nanoobjects in the form of specially designed nanoparticles, nanoscale particles with a linear size of less than 100 nm.
Nanoparticles and nanopowders, such as, for example, are more acceptable for modifying the technology and properties of building composites:
* carbon nanotubes;
* natural fullerenes shungite-shungite, shungite carbon, carbonaceous minerals:
• Shungite - an unusual carbon-containing species. Its singularity in the structure and properties of shungite carbon, and the nature of its interaction with the silicate components of cement. The unique properties of shungite stone give fullerenes molecules consisting of several tens of carbon atoms. The only shungite Deposit in Russia is located in Kizhi.
• Serpentinite and magnesian rocks: chrysotile-Mg6 (OH)8 Si4O10, antigorite Mg3 (OH)4Si2O5;
• Taurite is a new Kazakhstani mineral, it is a kind of natural polymer of cluster type, having in its structure both organic and mineral parts, not similar to the already known carbonaceous fossil minerals. In its composition it contains globular" ungraphitized " carbon with a metastable supramolecular structure of siliceous or carbonate type. Due to the geological metamorphoses that occurred with it, it did not become either graphite or diamond.
The use of Taurite in the road construction industry is due to its properties. It is a resistant black natural mineral pigment and filler in the production of various road construction materials including sealants.
* metal dioxides, which represent the first generation of products using nanotechnology developed by industry.
Industrial emissions deposited on roads and buildings in large cities annually amount to thousands of tons. In addition to the poisoned atmosphere, cities get dirty sidewalks and building facades.
Scientists are constantly in search of methods to solve this problem.
The new self Clean sealant is a product of nanotechnology. Created by Americans and designed to protect porous surfaces from all kinds of dirt. Materials coated with sealant acquire the property of self-cleaning. The process is possible only under the influence of sunlight or fluorescent light, "triggering" the reaction of photocatalysis. The photocatalyst in the sealant, titanium dioxide, under the influence of light destroys pollution at the molecular level. The resulting dusty residue stains are washed off with rainwater. The use of sealant is possible on vertical and horizontal surfaces.
Maintaining the appearance of buildings in good condition requires a lot of money. Despite this, public buildings in Europe are washed up to four times a year. With regular care it is not necessary to use aggressive detergents that negatively affect the condition of facade materials. Not far behind from municipalities and private persons: the contents of your home in order is a good practice. In many countries, this is a statutory obligation for homeowners. That's why European cities, big and small, look neat and elegant. This is probably the first thing that tourists from Russia pay attention to.
Major Russian cities also began to look good. Successful companies are serious about the cleanliness of the facades of buildings where their offices are located-this is part of the image. And many homeowners care what impression on others makes their house, including apartment. There were companies offering services for cleaning the walls of buildings of any height.
But in the Outback "bath procedures" for the facades of buildings - while a rare phenomenon. It is clear that such services are not cheap, especially since the cleaning of the walls of high-rise buildings engaged in industrial climbers, whose work is paid highly. The appearance of selfclean sealant can change the situation and not only simplify the care of buildings, but also make the air in the cities clean.
The sealant is easily applied to the treated surface, penetrates deeply into the pores of the material, while strengthening its structure and does not form a film on the surface. Dries quickly, does not emit harmful substances, odorless. The treated areas do not change the original color. The effect of the sealant is maintained for seven years. If the time to produce surface treatment, then their bringing in order can not worry for a long time.
In Russian regions with a humid climate, the appearance of fungi and mold on building structures made of porous materials is a common phenomenon. It is rarely possible to get rid of them forever, even with the treatment of strong means: the effect is eliminated, not the cause. SelfClean "preserves" building materials after removing bacteria, not allowing them to grow again on the cleaned surface. This property of sealant allows to save on cleaning of walls of buildings and a roof from porous materials.
After treatment with self Clean sealant, the slip coefficient on concrete road surfaces and stairs, paving slabs does not increase. Surfaces are kept clean for years. In the meantime, they are washed with a jet of high-pressure water. The use of this approach, as a rule, does not give a long-term effect.
Even more difficult to clean the roof of natural tiles. Although its service life is estimated in many tens of years, the beauty of the material fades over the years. Several times a year to clean the pitched roof is taken, probably not every owner even his own house. With a new sealant, this is often not necessary.
Self Clean sealant is used to cover new and long-used surfaces. Its timely application will make our cities attractive. The quality of life of the population will also change, because the main purpose of the new material is to reduce the impact of harmful emissions, which have a detrimental effect not only on architectural structures, but also, first of all, on human health.
Two-component non-shrink curing sealant "IZOL-31" is developed on the basis of thiol-containing polymer. It consists of two components - the main paste and hardener. After mixing the components, a thixotropic, easily applied paste is formed. After curing – elastic, rubber-like material with high deformation and strength properties.
* Sealing of road elements (paving slabs, curbs, sewage drains).
* Sealing of joints cut in concrete surfaces.
* Sealing of folds and elements of a metal roof (galvanized, black), attics, "lamps of a glazing".
* Sealing of inputs of communications, riveted connections.
· High adhesion ;
· High water resistance;
· High resistance to vibration loads;
· High strength, elasticity.
All these and a number of other indicators are improved through the use of nano-additives, for example: increasing the service life of the sealant from 10-15 years to 25-30 years with a thickness of 4 mm sealant layer, reducing the flow rate of sealant from 360 g/linear meter to 280 g/ linear meter (with a layer thickness of 10 mm and a seam width of 20 mm), increasing the warranty period and improving environmental safety.
Sealant Tiksoprol-AM of brand 052 for filling and repair of deformation seams of bridges, tunnels, roads, concrete plates of airfields.
Sealant Thixoprol AM brand 052 based on thiopol ester TPM-2 is a two-component cold-curing casting material. Sealant does not contain solvents in its composition (non-shrinkable).
Purpose and applications:
Sealant Thixoprol-AM brand 052, injection, is designed for sealing horizontal expansion joints of concrete airfield coatings, sealing cracks and crevices. The sealant meets the requirements of TU 405668-88. Operating temperature limits from minus 50 to plus 80 °C.
The sealant retains the filling properties that ensure the work on its application at temperatures up to minus 20 ° C.
The sealant is resistant to thermal gas blowing a stream of jet engines.
The sealant provides improved performance of the weld, resistant to UV radiation, changes in temperature "+/-". The projected service life of 5 years and above in compliance with the application technology.
The use of sealant, instead of compositions based on rubber-bitumen binders, without requiring heating and the use of expensive equipment, allows:
reduce repair costs
to improve the reliability of sealing
increase the service life of expansion joints. accordingly, the time between repairs increases
There is a positive experience in the use of sealant at various facilities.
Technological characteristics: the Sealant consists of a sealing paste of white color and vulcanizing paste of black color. Pastes are mixed with each other immediately before use in a ratio of 100:20, after which the composition is poured into the seam. Curing of the sealant takes from 1 to 7 days depending on the temperature and humidity of the environment.
Nanomaterials have significantly higher strength than their traditional counterparts. Roads built using nanotechnology can last 2 to 5 times longer.
To date, the potential of nanocomponents is not fully disclosed. In the future, scientists will have to solve many issues related to nanoscience, and to comprehend its deepest secrets. But despite this, nanotechnology is already having a very serious impact on the life of modern man.
Nanotechnology is a symbol of the future, the most important industry, without which the further development of civilization is unthinkable.