08.08.2019 change 08.08.2019
Karolina Duszczyk
Karolina Duszczyk

Polish roads. Scientists and road engineers are testing a new type of bitumen

Photo: PAP/Artur Reszko 13.04.2019 Photo: PAP/Artur Reszko 13.04.2019

Researchers will use funds from the industry to test new types of bitumen so that they be used in road construction in Poland. Polymer-modified surfaces offer a possibility of building roads without ruts, more resistant to frost, moisture and damage.

Modern types of bitumen, which will reduce the costs of road construction and improve their durability, will be tested by a scientific and industrial consortium from Gdańsk and Warsaw. The companies will fund research, in which scientists will test the properties of polymer-modified bitumen. If the assumptions are confirmed, the material can be used to build Polish roads.

The consortium includes engineers from the Gdańsk University of Technology, the Warsaw University of Technology and the Road and Bridge Research Institute in Warsaw. They will investigate how bitumen modified and highly modified with polymers affects the durability of the road surface.

WITHOUT RUTS

Highly modified bitumen is a new product of Polish refineries, but it is not widely used. The first applications proved to be promising, so the manufacturers decided to involve scientists in a research project that would verify the performance of the product, explains Dr. Bohdan Dołżycki from the Gdańsk University of Technology, who is the leader of the scientific consortium in this project.

In his opinion, the results of the project may also be of interest to road builders abroad.

"These bitumens are enriched with additives that increase elasticity, durability, resistance to fatigue and resistance to permanent deformations, ruts. They are intended for all roads - local, highways and motorways. More and more investors are convinced of the good quality of these products and begin to use them in their solutions. In Poland, there are road sections where these bitumens have been used" - says Dr. Dołżycki, assistant professor at the Highway and Transportation Engineering Department of the Faculty of Civil and Environmental Engineering.

"As far as I know, no one in the world has ever tried to carry out such a project. In terms of the use of highly-modified bitumens, Poland is one of the world`s leaders" - he emphasizes.

MORE EXPENSIVE BUT CHEAPER

The industrial consortium members are Budimex S.A., Grupa Lotos S.A. and Orlen Asfalt Sp. z o.o., which provide 100% funding for the research project. "Budimex strives to be a leader in the implementation of new technologies and new solutions, while Lotos and Orlen produce highly modified bitumens and want to scientifically verify their technologies and promote them" - says Dr. Dołżycki.

Patryk Demski from the Lotos Group that manufactures new generation binders declared a financial contribution to the research and development of high quality, durable bitumen road infrastructure in Poland. "We are looking for new ways to extend the durability of constructed road, while minimizing costs" - he emphasised.

The authors of new generation bitumens talk about future savings resulting from the high quality of the product. "The material itself is more expensive, but thanks to its good properties it is possible to apply thinner layers, which means saving. On the other hand, with the same thickness of layers, we get structures that will last longer. The investor will build a road that will last not 20, but 30 years. Then, the cost per year is smaller than with classic bitumen, which is confirmed by the analysis of the life cycle of the whole surface" - explains Dr. Dołżycki.

These assumptions require support with research, which will also result in scientific publications and the inclusion of modern bitumens in the catalogue of typical solutions used in road engineering (the Catalogue of typical flexible and semi-rigid pavements). What appears to be a clerical formality is in fact crucial for the project and will open the way to the widespread use of modern bitumens.

The catalogue was created several years ago when new generation bitumen did not yet exist. It does not include many other modern materials; only the most popular and best-tested ones are included.

"These materials can be used today, but require individual designs. Many investors are afraid of tha, because each individual solution means an increase in risk that something will go wrong. The catalogue is a list of typical solutions: proven, thought-out, calculated, with certain safety margins that allow to build roads safely" - explains Dr. Dołżycki.

Solutions from the catalogue can be widely used and do not require individual designs. If modified (PMB - polymer modified bitumen) and highly modified bitumen (PMM HiMA - highly modified asphalt) were to replace the currently used road bitumens, then asphalt concrete surfaces with such bitumen should also appear in the catalogue.

"The layout of road pavement layers and their thickness are most often determined on the basis of this publication, but the current catalogue only assumes the use of unmodified bitumen and does not fully exploit the potential of modified bitumen types, in particular those highly modified with polymer. Our goal is to prepare and add new pages taking into account the use of this bitumen" - adds Dr. Piotr Jaskuła, deputy head of the Highway and Transportation Engineering Department at the Gdańsk University of Technology.

STRESSING BITUMEN

Tests will be carried out mainly in laboratories. They will show whether the new type of bitumen is more durable and has better properties than the classic type. Engineers will also evaluate the life cycle of the surface and its impact on road maintenance costs.

"We will extensively test the bitumen-mineral mixtures` resistance to destruction. We will test their resistance to fatigue, water and frost, resistance to permanent deformations (formation of ruts) and their resistance to cracking. We want to demonstrate their advantages over classic bitumen" - says Dr. Dołżycki.

Engineers will also carry out fatigue tests that show how the material withstands small deformations. The more durable it is, the longer it will last on the road.

"We have a specific way of loading in the roads. There are no great forces that load the surface. The existing loads are small, but repeated very often. The surface deforms under each wheel, and we check how many such deformations the material will withstand. During fatigue tests, we test such deformations a million or more times, and on this basis we predict how the material will behave in the future" - the scientist says.

The work will be carried out as part of the research program "Optimizing the construction of the asphalt concrete road surface by using modified bitumens". According to the scientific leader of the project, the Ministry of Infrastructure and the General Directorate of National Roads and Motorways are interested in the results. This is related to the implementation of the National Road Construction Program for 2019-2025.

The research program started in May and will last 1.5 years. The catalogue will be created by the end of 2020, but it will still need to be approved by the road authorities. Scientists expect that in 2021 it will appear as a document approving the widespread use of the latest bitumens on our roads.

PAP - Science in Poland, Karolina Duszczyk

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