Very recently a video appeared on the Internet, amassing a large viewership in a short time. It is of a new way of laying public roads from plastic slab – a way to fast, convenient and eco-friendly roads. Meanwhile, Russia has its own innovative technology for producing prefabricated roads in short periods of time – although, as the main material is, taking into account the peculiarities of our country, large-size reinforced concrete slabs instead of plastic. At the same time, the laying speed is impressive: about a hundred linear meters of the road in a working shift.
The authorship of the Russian technology of “fast road” belongs to the Chelyabinsk company “Innovative technologies in construction” (“ITS”). Since 2010 the Ural enterprise specializes in the development and implementation of new solutions in the field of installation and reconstruction of roads and railways.
Developing the technology of quick-mount road pavement, the specialists of the company set the goal to create a product equally suitable in all climatic and geological zones of our country – and at the same time, which would be economically expedient for road construction companies.
Thousand “but’s” of the Russian road
Today in Russia various materials are used for road construction, each of which, to put it mildly, is not ideal. Compressed ground roads are unstable to the effects of rain and wind – and compacted in places by chemical reagents, the soil can adversely affect the local ecology. The most common, the asphalt pavement, with its availability and low cost, requires a hard base and is very vulnerable to temperature factors: it melts in the summer and cracks in the winter. Monolithic concrete coating is of high quality takes a long time (about a month) to harden. In addition, all these types of coatings have limitations on the construction season and require certain costs for repairs and maintenance. Obviously, the best solution for the road industry would be to create a durable coating that is inexpensive to operate and does not require annual repair work.
Quick-mount, long wear?
The task of creating such a product is priority of the specialists of “ITS”. The new coating is to be cost-effective in terms of laying, maintenance and repair, to serve 20-30 years, fit into any time of year, and also to work with loads of 12.5 to 20 tons per axle.
Of course, to create a product of all these characteristics simultaneously is currently impossible. Therefore, the work on it was carried out in several stages. The first of these was the search for the optimal formula concrete having greater strength, low water absorption and a high resistance to frost. Next is the development of unique structure of prestressed concrete slabs and its connection elements. Finally, the technology of paving elements was determined by hoisting and mounting via the hydraulic equipment. Below is the analysis of the solutions reached.
The choice of material and creating structure
The cement used for the needs of road construction in Russia often has low indicators of strength, water absorption and frost resistance. For this innovative pavement “ITS” developed an original composition and concrete production technology strength class B60, frost resistance of over three hundred cycles, water absorption of not more than 14 and the abrasion resistance is 2.5 times over what is required by GOST 13087-81. The resistance to crack is provided by the use of special sands and gravel fractions 3 – 10 mm. It is interesting to note that all of the components of concrete are of domestic market origin, with the exception of additives and silica fume plasticizer “Glenium”, which is not produced in Russia, but it is very often used in our country.
Specialists of “ITS” developed plate structure with a strained armature shaft and meshes, and metal forms for their serial production. At the edge of each of the plates there are four conical holes, through which it is convenient to pick up and handle with care. Inside the plates there are channels for subsequent screed in roadbed using protected steel ropes. Plate Dimensions (length / width / height) – 6000x3500x130 millimeters – optimal for their transportation by rail or road train. Production of slabs is carried out in the factory that provides a consistently high quality, the possibility of producing and shipping year round for quick road introduction all over Russia.
The semi-cylindrical groove along the perimeter of the plates is used to install the elastic element between the plates made of special resistant rubber preserving operability for at least thirty years. Feed “Ф”-shaped cross section adjacent the surface prevents the concrete slabs from direct contact, but elastically transmits a plate on the plate vertical load from passing transport wheels.
Road construction technology
The base for the traditional road is made based on the geology, topography, the winds, precipitation and depth of the groundwater; gravel base must be very tough. Modular concrete roads do not require such a rigid base. It is laid on the planarized surface of the sand, which is leveled, sealed and covered with a film of polyethylene waterproofing intercepting flow of soil moisture.
Next up, the connecting plate is laid – and then thereto through an elastic element the main plate. The result is a chain of 6-8 major plates – after which at the end of the connecting package is placed again. Laying is done very accurately to coincide holes for routing cables.
When laying a single-lane road plates can be lifted by the strapping holes with special grippers and straps, placing them on the plate perimeter. When installing two- or multi-lane roads plate due to the two plates touching with the side surfaces the use of snags in this case is impossible: only suitable grippers.
Base plate, as already mentioned, similar to the bracelet link, has through holes for the wires. Connecting plate channels extend from openings at the ends to the pockets on top of the working surface. With hydraulic connecting ropes are passed through the whole chain and slabs in tension wedge anchors are fixed in the coupling pocket plate. On the other end plate wear hydraulic tension machines that operate each rope tension force of ten tons and then fixed in the tensioned state by the same wedge anchors.
During the construction of two- and multi- lane roads parallel plates stacked are tightened with ropes which are passed through the transverse channels – in this case the wedge anchors these channels are placed on the sides of the plates (roadside).
Innovative road in Belgorod
More precisely, the first “pilot” road section constructed in accordance with the new technology. It appeared in June 2013 near the village of Brodok in the Belgorod region – a road length is 180 meters, as such space needed to develop the optimum scheme workflow for maximum performance.
The completed project has confirmed full compliance with the road surface parameters declared by the manufacturer, indicating that the great efficiency of the innovative project.
In 2013 a new highway construction technology has been patented and has been approved at a meeting of the expert council, and later – a working group to improve the public procurement of innovation in the transport sector of the Ministry of Transport of the Russian Federation. The technology developed by the company “ITS” was officially included in the list of technologies recommended by the Ministry of Transport to public procurement.
Probably every developer of a new technology tends to test it in not only those conditions in which it is designed, but also in extreme load conditions. “ITS” company with its technology of the rapid pavement was no exception.
In 2015, at the site “Alabino” a World Championship tank biathlon took place, which was attended by 57 teams from 17 countries. Complex obstacles meant for the participants in the competition, among other things, included a scarp and steep – up to 85 degrees – a cut of a hill that is almost a vertical wall in practice. As an escarpment coatings the plates of concrete slabs PAG-14 and PAG-18 according to GOST 25912-91, as well as OOO “PSK-Profit” improved stoves PAG-14 Concrete B60 frost resistance F200, developed by technology company “ITS” were used. Plates withstood the onslaught of 40-tonned armada of armored vehicles – and all damage to the coating caused running heavy machinery, visually recorded by experts and by the end of the competition have been subjected to rigorous analysis.
In 2016 in Ostrogozhsk, near Voronezh, a slightly smaller tank biatlon took place. The participants showed during the competition mastery control of heavy machinery and military off-road vehicles – including the passage of the segments with obstacles “land with stones” and “Track”, which was mounted by a partner company of “ITS” – “PSK-Profit.”
To create these obstaclesan innovative technology in the field of reinforcement have been used, including – composite rebar and slabs made of concrete grade B60, manufactured and arranged in accordance with the technology described above. The possibility of rapid installation with all weather conditions came in handy – if necessary, the design can be quickly dismantled and moved to another location, then reassembled.
During the time that the games lasted, obstacles have been seriously tested in a variety of loads, but it retained its integrity. And the military involved in the passing stages of games, noted the high level of complexity of passing obstacles.
But, of course, the new product of the road construction industry testing with tanks and armored vehicles is a kind of extreme, set up to see the threshold of strength of fast-concrete structures. Much more widespread use of new technology is in civilian life; first of all – it’s everyday tasks associated with intensive freight. The technology developed by the specialists of “ITS” has all the necessary permits and is ready for use, we have no doubt will see use in the coming years.