On 19th February 2015 an international bitumen conference, the first of its kind in Estonia, was held in Tallinn University of Technology. A total of 123 participants from 9 countries registered for the conference. Speakers included recognised professors and researchers in the field of bitumen and asphalt pavement research.
The first presentation was by Professor Hussain Bahia who spoke about experiences he has gained in the course of the development and introduction of Performance Grade (PG) system in the United States of America. He provided a thorough overview of applied methods and tests and spoke about further developments of the PG system that he is currently working on in Qatar. Professor Bahia emphasised that while bitumen is an important component to work on, it is equally important to pay attention to the composition (i.e. the recipe) of the bituminous mixture. Without proper planning of the mixture and establishment of relevant requirements it is not reasonable to spend funds on good and expensive bitumen. Professor Bahia demonstrated current US principles of composing the PG mixture recipe and explained how the structure of gravel in the mixture is measured by means of iPas method.
He also spoke in detail of the tests that have been carried out in UW-MARC with several types of bitumen from Estonia. He gave recommendations as to the methods of modification that could be used in Estonia so that available bitumen would be suitable for use in Estonia according to the PG climate map.
The second speaker was MSc Sven Sillamäe who talked about the bitumen study commissioned by the Estonian Road Administration. As it is the first study of this kind in Estonia, the first stage of the study focused on the collection of basic data in the field of both rheology and chemistry. Sven Sillamäe compared the pen Grade approach implemented in Estonia to the Performance Grade approach implemented in the US for assessing bitumen parameters. He pointed out a weakness of bitumen produced on the basis of paraffin oil – the presence of paraffin wax in bitumen, and emphasised that it is necessary to determine said presence.
Dr. Migle Paliukaite provided an overview of a bitumen study in Lithuania that was conducted in the course of her Doctoral thesis. In her research she paid detailed attention to the chemical approach in identifying the characteristics of different types of bitumen. According to her the SARA method is one of the most important indicators if observed before and after the bitumen has been aged. However, Dr. Paliukaite pointed out a weak link in the European standard and the PG system, namely the lack of a good and adequate method for determining adhesion.
While speaking of her studies in Queens University in Canada Migle Paliukaite described in detail the tests used there for determining bitumen parameters, one of such tests being the DENT test.
The fourth speaker was Professor Terhi Pellinen from Aalto University in Finland. She began by speaking of studded tyres and the effect these have on our roads. She also described the tests that have been implemented in Finland in order to better assess the effect of studded tyres on road surfaces. A widely used technological solution for alleviating the effect of studded tyres in Finland is hot recycling of asphalt surfaces. Professor Pellinen provided a good overview of the development of this technology in Finland. She also spoke in detail of problems related to pavements and of the solutions the Finnish Road Administration has found for them. Professor Pellinen had a very high opinion of developments in regulating the use of filler.
Conference organisers received positive feedback from the speakers who were very pleased with the conference theme. The speakers also mentioned that more conferences and workshops should be organised on this topic as these help generate new ideas that in turn contribute to development. Feedback from the audience was also positive; the topic was important for them. Estonia’s first bitumen Conference helped prepare the ground for future discussions on this subject, thus contributing to quality development.
Mr Aivo Adamson, Director General, Estonian Road Administration
Bitumen research in Estonia
Mr Sven Sillamäe, TTK University of Applied Sciences/Tallinn University of Technology, Estonia
Results of bitumen research in Lithuania
Dr Miglė Paliukaitė, Vilnius Gediminas Technical University/Queens University, Lithuania/Canada
The role of bitumen in asphalt mixtures
Prof Terhi Pellinen, Aalto University, Finland