What determines the quality of roads

What determines the quality of roads

It is no secret that the quality of roads – it is what every driver is concerned about. But few people know that the traffic load of the roads in Tatarstan increases annually, that leads to an increased wear of the roadway. How to increase the 'life' resource of exploitation in such conditions? The solution to this global problem is being worked out by the road transport sector of RT in the close cooperation with TAIF group of companies – the Tatarstan manufacturer of road bitumen, which follows 'the dictates' of the RF state standards and seeks to improve the quality of the product according to the increasing requirements of the road construction. Despite the fact that the new GOST 33133-2014 on the quality of bitumen will be valid in Russia since 1 September 2016, the subsidiary of the holding company TAIF-NK JSC in June starts developing the production of bitumen according to the new standards.

Ruttings, cracks, potholes, or Why the road surface loses its flatness

The strength and durability of asphalt pavement are essential for a continuous operation of high-speed roads. However, with the growth of motorization of the population and the increasing volumes of inter-regional transportations, the road network of the metropolis has begun to experience enormous, non-designed traffic loads.

As the Minister of Transport and Road Management of RT Lenar Safin stated, daily load of the Big Kazan Ring is up to 50 thousand cars, that exceeds the original design load. The usage of the studded tires during a wintertime has an especially strong negative impact on the road surface, as well as the frequent temperature fluctuations — the workers call them 'zero crossing'. 'In these circumstances, the regional roads do not withstand heavy traffic,' the Minister said.' For this reason in Moscow they update the upper asphalt concrete pavement every three years. We will inevitably come to this decision, too,' he said.

There is also another solution – to improve the quality of the roads, to increase the durability and resistance.

In Moscow they update the upper asphalt concrete pavement every three years. We will inevitably come to this decision

Around this topical theme, there have appeared many myths and misconceptions that hinder to consider the problems of road construction objectively. Having studied the secrets of the quality of European roads, the experts came to the conclusion that many our ingrained stereotypes are far from reality. So, in the construction of roads in the countries such as Germany and Finland, it is primarily used high-strength reinforced concrete pavement, often without asphalt 'coating'. But it is a very expensive road construction, although it is much more durable. Second, it is the use of only granite and marble fillers with very high compressive, tear and abrasion strength in the asphalt mixture. Third, it is very strictly regulated technology of preparation of asphalt mixture, consisting of a series of successive operations. Breaking at least one such operation, you will fail to obtain high-quality asphalt pavement. For example, the overdose of bitumen will inevitably lead to the rapid formation of grooves on the roads, but will greatly facilitate the laying of asphalt on the roads.

Breaking at least one such operation, you will fail to obtain high-quality asphalt pavement. Photo: elitat.ru

From the whole complex of the procedural requirements in the production of asphalt, bitumen, although as an important element for the construction of good roads, is not the main argument. From the manufacturers and the producers of bitumen there is only one requirement — to conduct production strictly according to the requirements of GOST on the quality indicators.

Of course, the strict observance of the technology of preparation of high-quality asphalt before laying inevitably leads to a rise in the cost of road construction, as it requires individual equipment for each operation, expensive inert materials (which are almost not extracted in the Republic of Tatarstan), an increased consumption of thermal and electric energy, and, of course, it increases time expenditures.

Another impetus for the transition to the modern technology is the Russian requirements to the operational condition of the roadway and gradients. In the calculation and design of road pavements, it should be taken into account a potential traffic flow intensity, and the thickness of individual layers should provide security. The pavements should have sustainable flatness, and possible deviations from the regulatory level values along the axis, the crossfalls should not exceed 5-10% of the design values, which is not always observed in practice. The design of the road surface must have gradients that must remove all water residues from the roads without any coercive methods, including without atmospheric evaporation.

The subsidiary company of the holding – TAIF-NK JSC – is the largest producer and supplier of road bitumen, that is supplied for the road construction in Tatarstan. It accounts for 64% of total volume of used road bitumen in Tatarstan, including binders, polymer bitumen and road bitumen emulsions.

Currently, TAIF-NK produces road bitumen BND 60/90 and BND 90/130 according to GOST 22245-90. As raw materials they use tar, fuel oil and other products. Bitumen, made from such raw materials have a high extensibility at 25 º C, the plasticity and adhesion, resistance to sub-zero temperatures. But one of the indicators, namely the quality after artificial senescence, from a year to a year had and has instability in its numerical value, although it is always within the tolerance defined by GOST standard.

How to transit to new conditions of the road construction in Tatarstan?

From 1 September of 2016, the use of bitumen that meets the standards of the new GOST 33133-2014 becomes mandatory in road construction. It was approved by the Eurasian Economic Commission for the distribution in all countries of the CIS, and it sets new requirements for quality indicators. The compliance with the new GOST is a condition for participation in federal tenders of Rosavtodor and Avtodor, so the road contractors now have to choose their suppliers of raw materials. For a full discussion of these issues, the management of TAIF group of companies on behalf of the President of Tatarstan gathered all stakeholders in the central office. The meeting was attended by the Minister of Transport and Road Lenar Safin, his deputy Artem Chukin, the director of state public organization Glavtatdortrans Eduard Danilov, representing the interests of the state customer in the construction of roads, as well as the heads of the leading road companies — Deputy Director General of Tatavtodor JSC Ildus Faskhutdinov and CEO of Alekseevskdorstroy Foat Valiyev, the director of Glavtatdortrans SPI Eduard Danilov.

The roaders confirmed that the fault of the grooves on the new road built for the Universiade is not the quality of bitumen

'On the agenda there remains the question of improving the quality of road construction. We would like to present to you our achievements in the field of the production of bitumen and polymer-bitumen binders and to inform about our approaches in the production of polymer bitumen. For us it is extremely important that in Tatarstan there were built only high-quality roads. Therefore, we make every effort to provide high-quality road bitumen,' addressed the audience Director General of TAIF JSC Albert Shigabutdinov.

Nizhnekamsk bitumen meets the requirements of new standards

The transition to the production of road bitumen meeting the new GOST 33133-2014 is not very difficult for Tatarstan producers of TAIF group. Although it should be noted that more simple and more cheap the road bitumen is obtained from those oils that have a specific group composition of heavy components. Oil of the Republic of Tatarstan is definitely not suitable raw material for the production of bitumen — it has a lot of oil-resinous and paraffin compounds, that is good for the production of raw materials for the petrochemical industry, but negatively affects the technology of bitumen production. Besides, the production of bitumen at the constantly renovated, with large capital investments plants, which already for several years is not cost effective for the refinery — bitumen is not profitable for the refinery.

Since September of this year, the federal legislation required all contractors in the construction of roads to transit to the bitumen on the newly introduced standards. These questions became the subject of extensive debate by all stakeholders in the first part of the meeting. During the discussions, they highlighted the need to ensure the stability of quality of Nizhnekamsk bitumen according to the new standards.

Since September of this year, the federal legislation required all contractors in the construction of roads to transit to the bitumen on the newly introduced standards

According to the Deputy Director General of TAIF on refinery and petrochemicals Vladimir Presnyakov, the scientific and research works in TAIF-NK were initially set with the aim to achieve stability of quality of bitumen, including on the requirements of GOST 33133-2014. The specialists of TAIF-NK JSC went the different way of a simple oxidation of tar in bitumen, since this standard method that is used by most Russian refineries, makes it impossible to stabilize all indicators of quality of bitumen of Tatarstan oil. There was proposed a method of so-called 'peroxidation-dilution' of raw materials for bitumen. This way is much more complicated and requires additional expenses, but industrial experiments confirm the correctness of the chosen path. At the same time, Vladimir Presnyakov asked the question: why and for what reason on a new road built for the Universiade from Kazan to the airport there appeared a large groove? Is road bitumen the blame for this? The answer was evasive and condescending, but they definitely confirmed that the fault for the grooves on the new road is not the quality of bitumen.

The Director General Alekseevskdorstroy Foat Valiev confirmed the quality of Nizhnekamsk bitumen has significantly been improved, but the other Russian producers have problems.

Quality and safe roads — the common goal of TAIF-NK and road contractors

Another issue discussed at the meeting – when to stop the release of 'old' bitumen and to transit to 'new' one? After all, before the adoption of the new GOST the roaders had become 'bound' by the obligations under previously signed annual contracts for the supply of bitumen. To meet the wishes of road companies, Director General of TAIF JSC Albert Shigabutdinov declared that in 2016 they are ready to supply bitumen of the new standard and probably for the same price under the previously signed contracts, which pleased the contractors.

Developing the theme of the transition to the new standard, Deputy General Director of Tatavtodor JSC Ildus Faskhutdinov suggested not to rest on our laurels, but to improve the technical parameters of Nizhnekamsk production. 'The introduction of GOST 33133-2014 is the first step in the harmonization of Russian standards of road materials with the international system of compositions design Superpave,' he said. 'So we need to work for the long term. Today, technology is aimed at durability, and a decisive role is played by the binders. Superpave standards also include an indicator such as ageing, and its implementation is a difficult task. There are more complex requirements. Therefore, I propose to create a joint with the Tatavtodor working group which will deal with the design of complex compositions of the mixes,' he said.

Deputy Director General of Tatavtodor JSC Ildus Faskhutdinov suggested not to rest on our laurels, but to improve the technical parameters of Nizhnekamsk production

But how much will the bitumen of the new state standard change the quality of the roadway? Whether it will be durable and resistant to cracks and grooves? These questions asked themselves, or so to say, were in the air. Finally, Vladimir Presnyakov directly asked the roaders, whether will roads with bitumen of the new standard serve longer than usual?

'Unfortunately, no. Because the roads will still bear a high load,' was the response from the roaders. Then they came to the conclusion that the bitumen is only a binder, and the overall quality depends much more on the quality of inert materials, additives in the form of surface-active substances, the compliance with the technology of asphalt mixtures obtaining and the methods for laying of the roadway.

The Director General Albert Shigabutdinov put the end to the discussion.

'The activities of TAIF-NK as a manufacturer of bitumen and polymer materials for Tatarstan road companies, which pave the asphalt surface, must be subordinated to a single goal — to improve the road quality,' he said. 'If our partnership produces GOST bitumen, you should make good roads. Or we will not conduct unprofitable for us production of bitumen. Poor roads do not need quality bitumen.'

If our partnership produces GOST bitumen, you should make good roads. Or we will not conduct unprofitable for us the production of bitumen. Poor roads do not need quality bitumen

Polymer materials – a new stage in the road construction

The meeting consisted of three parts. In the first part they actively discussed the old and new GOSTs of the bitumen production. At the second part, TAIF group of companies presented the own analysis of the production technology of asphalt concrete mixture. The producer should understand the whole technological process for the improvement of the work in the production of road bitumen. The leadership of the sector Ministry undertook to study the materials of TAIF group of companies on the production of asphalt and to give an opinion, but much later.

The third part was devoted to the future, the planned production of polymer bitumen. One of the tools of the quality improvement of the roads is the use of polymer materials in asphalt, which is the daily practice in the road industry of all developed countries. After all, the quality characteristics of bitumen are improved generally through the introduction of polymer modifiers that reduce the sensitivity of bitumen to temperature changes, expand the temperature range of its operation, increase its elasticity and strength, increasing the service life. Keeping up with the times, TAIF group of companies for more than 3 years has been working hard at mastering the production of polymer bitumen at TAIF-NK and Nizhnekamskneftekhim, including in 2016, three newly purchased plants for production of polymer-bitumen and its packaging in rigid containers will start working.

In its turn, the Ministry of Transport and Roads of the Republic of Tatarstan this year has toughened the requirements to the technical parameters of polymer bitumen, taking into account the increasing load of the road network of Tatarstan.

'We are toughening the Russian requirements (to the polymer binders — editor's note) and set the technical parameters higher than are adopted in the Russian Federation (i.e., it is about the adoption of the Tatarstan standard – editor's note). In this direction it is important for us to know what a Tatarstan manufacturer will offer,' said the Deputy Minister of Transport and Roads Artyom Chukin, 'and whether it will be able to produce such bitumen.'

Production of Polymer-Bitumen Binder in TAIF-NK was the topic of the third part of the meeting. Alekseyevskdorstroy uses divinyl-styrene rubber made in Korea in its unit built in asphalt factories. However, this rubber is very expensive. TAIF-NK PJSC used rubber made in Voronezh for trial lots for polymer-bitumen production. It is also very expensive for asphalt production.

It is supposed the Nizhnekamskneftekhim rubber will be much cheaper than the rubber purchased from other Russian and foreign producers. Photo: press service of Nizhnekamskneftekhim PJSC

Works on the production of its own divinyl-styrene rubbers have being carried out during 5 years in Nizhnekamskneftekhim. And there are results – rubber used in rubber industry is produced. Trial deliveries are tested in Michelin, Pirelli, Bridgestone.

Divinyl-styrene rubber of a bit different polymerisation structure is needed more for the production of polymer bitumen than the rubber produced today in Nizhnekamskneftekhim. It is cheaper, of course. It is expected there will be manufactured over 2,000 tonnes of divinyl-styrene rubber in Nizhnekamskneftekhim during 2-3 months. It will be enough for polymer bitumen production in TAIF-NK during a year.

Moreover, other Russian producers of polymer bitumen will be able to buy this rubber. Vladimir Presnyakov supposes the Nizhnekamskneftekhim rubber will be much cheaper than the rubber purchased from other Russian and foreign producers because such a production doesn't require any specific characteristics that are necessary for rubber goods and tyre industry.

But these technical and technological changes in bitumen production, as it is expected, will appear together with the launch of the Heavy Residues Deep Conversion Complex in TAIF-NK this autumn. As a result, the enterprise is to get an 'absolute raw material' in the form of so-called 'pure' goudron without all those disadvantages and problems that appear in the first conversion of the regional oil. Straight-run goudron will pass an additional 'heavy' high-temperature hydrogenation under extremely high pressure. It will inevitably destroy all problematic, heavy 'oil' combinations from the Tatarstan oils, including all unnecessary heavy wax combinations. It is supposed it will be technologically easier and cheaper to produce road bitumen of the new GOST 33133-2014, and it won't be too difficult to maintain the stability of the quality of road bitumen like now.

In addition, TAIF-NK is simultaneously thinking about a possibility of production of polymer bitumen only in the future. Its quality will exceed any standard oil bitumen. This is why it is necessary to develop together with road workers of the republic and, first of all, fix a reasonable price for this bitumen. Year-round production and delivery of road polymer bitumen against today's seasonal production is another important problem that should be solved. And taking into account the fact that petrochemical products of the holding are of high quality and in demand in world markets, polymer bitumen has been already in demand. The new production will mainly be designed for export and increase the profitability of bitumen production due to a higher price of the end product.

By Luiza Ignatyeva. Photo: Maksim Platonov