The road industry is considered conservative in terms of the use of new technologies and materials. Nevertheless, in recent years, it has become the center of attraction for new ideas in the most relevant areas. So, the use of secondary raw materials, for example, ash and slag, in the construction of highways is promising. The technology of strengthening natural and man-made soils sounded in a new way. New compositions are being developed and successfully tested for the maintenance of the automobile network, and, in particular, for dedusting paved roads. The problem remains the massive introduction of these and other innovations, but the trend has been set, and the road industry says "yes" to new technologies.
The Bermuda Triangle
The discussion about the essence of ash slags has been going on for a long time. From the point of view of ecology, this is large-tonnage waste of the 5th hazard class. However, with proper processing, they can become a replacement for traditional materials used in road construction. The secondary has a huge potential, because traditional materials are growing in price, logistics is becoming more complicated, but at the same time it is impossible to prevent the disruption of the implementation of national projects. Large - scale the use of ash and slag would contribute to solving a potential environmental problem. Currently, more than 1.5 billion tons of such waste are stored in various regions of Russia, and this problem is especially relevant for Siberia and the Far East. There is a similar problem in foreign countries, but it is being solved there: in China, the volume of formation of coal combustion by-products is 395 million tons, while the volume of utilization reaches 67%; in the EU - 100 million tons (90% utilization), the USA - 118 million tons (42% utilization). In India, for example, mechanisms have been introduced at the legislative level that quarantine the use of fossil non-metallic materials if there are secondary material resources nearby. In Russia, this figure does not exceed 10%.
What is the reason? After all, the existing regulatory framework in the Russian road industry does not prohibit the use of materials of man-made origin. However, in practice, the possibility of their application is drowning in the "Bermuda triangle" between the customer, contractor and supplier, who do not want to take risks with new materials, said Dmitry Borisov, General Director of the Center for Innovation of Building Materials and Technologies LLC. If you look on the economics of a road construction project, the ash-slag-based material is used in the foundation of roads, and this is the cheapest, and the benefit from it is minimal, while the risks for the participants in the process are calculated in tens of percent relative to the cost of construction. At the same time, the supplier of the PSU (coal-fired power plants) is least at risk, since this is auxiliary production for generation, and all costs for disposal are included in the tariff. "So it is necessary to look at balancing the ratio of risks and benefits," the expert recommends.
There is no widespread practice of using secondary resources in Russia, as abroad, due to administrative barriers, legal conflicts and "gray areas" in legislation, agrees Nikita Osokin, Deputy director of the Center for Industry Research and Consulting at the Financial University under the Government of the Russian Federation. Indeed, Federal Law No. 488 "On Industrial Policy in the Russian Federation" suggests the term "secondary raw materials", equates processed waste to a product. However, the question remains open: is generation capable of creating such a value of this product to encourage how to buy it? So far, all participants in the process are rather inert, but the expert emphasizes that it was the power engineers who were the first to independently approve for themselves the target for the utilization of ash and slag: 15% by 2024, 50% by 2035. However, this activity is explained by the fact that generation is being squeezed by environmental requirements: storage in dumps is now becoming more expensive, and this is already an extra cost that you want to avoid or minimize.
In search of solutions
Currently, the issue of the use of secondary raw materials is being discussed in the Ministry of Transport of Russia together with the FAA "ROSDORNII". Moreover, the vector of implementation of joint plans is aimed not at theoretical research, but at the practical application of these materials. "Enough tests and studies have already been carried out, and the results of R&D are on the shelf," commented Yuri Ryumin, head of the Project Office for Science at the FAA ROSDORNIA. - We must fit into the concept of the integrated plan of the Ministry of Energy of Russia and identify pilot projects, analyze the composition of road works within the framework of the national project of the BCD, in order to prove the effectiveness of the use of ash slag in road projects". At the same time, being an expert body, RosdorNII offers to act as a platform that will unite customers, road construction companies, design organizations and generation.
An additional measure for the mass use of ash and slag in the economic turnover of Russia could be the initiative of the regulator. For example, within the framework of a comprehensive plan for a municipal order, it would be possible to establish such a measure that any road construction projects (or capital construction; reclamation of disturbed lands; liquidation of landfills, landfills, etc.) necessarily provide for the use of ash and slag materials with technological capabilities. Currently, the Ministry of Transport of Russia is not ready to consider specific road facilities, but agreed that such projects should be regularly monitored. At one of the joint meetings with the Ministry of Energy of the Russian Federation, it was agreed that within the framework of promising road construction projects, the possibility and feasibility of using ash and slag materials will be evaluated on an ongoing basis. For their part, they plan to create own association, whose tasks will include the development of a cyclical economy and the use of secondary raw materials.
Strengthening of soils
Ash slags are not the only example of innovations in the segment of road construction using secondary resources. A related topic is the strengthening of natural and man-made soils. In particular, the development of materials based on converter slags of the Novolipetsk Metallurgical Combine was carried out by LLC "Stream" and LLC "BFB". Together, a modifier for strengthening the soil "Acropolis fuel" was developed, which allows to increase the strength of the resulting soil composite by three times, the modulus of elasticity by almost four times, reduces water saturation and increases the durability of the final material. The material can be used in various fields, replacing concreting and reducing the cost of construction work. It is suitable for performing all types of road works - construction, reconstruction, overhaul and patching - in all climatic zones. At the same time, savings range from 30 to 70%, depending on the region, the speed of work increases up to 6 times compared to traditional technology, said the general director of LLC "Stream" Andrey Glukhov.
It would seem that such technology should be given the "green light" in all regions, but in practice everything turned out to be not so simple. "Like all Russian manufacturers, we are faced with the problem of the evidence base of the effectiveness of the technology," the expert commented. - Compositions for strengthening soils of foreign manufacturers presented on the domestic market declare their characteristics and at the same time are perceived as a given. In the case of domestic production, it is necessary to collect a huge evidence base every time, conduct a lot of laboratory and field tests. After all, even the results of laboratory research in one region are not evidence for the application of this innovation in other subjects."
Nevertheless, developers consistently promote their developments with the use of ash and slag and ferrous metallurgy waste. The list of objects made using the soil modifier is constantly being updated, and the number of successful tests is also growing. In particular, the Ministry of Emergency Situations is interested in the material. The company "Severnoye Dorozhnoye" was also created. construction", the main activity of which will be working with materials based on ash and slag. Specialists also work with other secondary resources, for example, phosphogypsum is promising, as well as secondary material formed after burning oil-bearing waste. "At the base of the roads, we always achieve results of more than 7-8 Mpa, which ensures a decrease in water saturation and, as a result, durability and high performance characteristics, which increase the inter-repair time for road repairs," Andrey Glukhov summed up.
Without noise and dust
Another direction in terms of innovations for highways concerns not construction and repairs, but off-season maintenance. In particular, we are talking about the technology of dedusting public roads. The topic is not new: such compositions have been developed before, but for unpaved roads, roads with low traffic intensity, rural roads, with a transitional type of coating. Now this problem has acquired a special scope and concerns roads with asphalt concrete pavement, especially in megacities, where smog from exhaust gases and dust particles regularly occurs. At the same time , substances, which are proposed for dedusting in industry road methodological documents, can not be used on roads with asphalt concrete pavement in the cold period and off-season, because they lead to the formation of slipperiness.
"Together with specialists from the Northwestern State Medical University, we investigated the road estimates accumulating on the streets of cities and found serious concentrations of heavy metals that remain on the road lane as a result of vehicle traffic," said Anna Klimentova, head of the staff of the National Association for Winter Road Maintenance. - Fine particles were found in the estimates, which appear due to the wear of brake discs, tire abrasion, various oils, dust - quite carcinogenic substances. They are mixed with sand, which road services use in winter as an anti-icing material, crushed and lifted up with air currents, and people breathe this."
Therefore, it became necessary to choose such a dedusting solution that can be used in winter and in the off-season on asphalt roads. Such a composition was developed jointly with the administration of Novosibirsk. "We chose one composition out of four, which, on the one hand, did not reduce the coefficient of adhesion, and on the other hand, effectively kept dust on the road," said Anna Klimentova. - In 2020, we conducted full-scale tests in Kazan. It turned out that the composition reliably dedusts the road and withstands heavy rain. We also conducted an experiment with vacuum sweeping: after dedusting, the estimates become wet, and it is easy to remove them mechanically."
However, the developers of this innovation are also faced with the fact that it is impossible to start using it en masse due to the lack of regulatory documents. "Therefore, we have developed a national standard, which includes technical specifications for dust suppression on dirt roads, coal mines and quarries. And we made a separate table of technical characteristics that dust suppressants for asphalt roads should correspond to," she continues. - Currently, they are used in a number of Russian cities and collect good reviews."
However, the problem is not only in the absence of standards: the fact is that dust suppression, in principle, is not specified as a type of work for winter or off-season maintenance, respectively, and funds for it are not included in the estimates. Anna Klimentova addresses to
RosdorNII with a request to jointly solve this problem - so that innovations reach road services and they can be legally used, increasing the comfort of movement on highways and the level of environmental friendliness in cities.
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