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Conclusions on 14th Colloquium on Asphalt and Bitumen

Asphalt is a construction product that can be fully re-used in the new asphalt (100 % recycled) and also the residual energy value can be utilized.Due to the limited resources of raw materials (natural aggregates, bitumen) with various production and laying techniques the reuse of asphalt and the use of alternative materials (such as. black slag, rubber, ...) are encouraged. All of the above apply only when at least equal quality of the product is guaranteed and when there is no additional environmental impact.

The bitumen quality - as the key input material for the optimal quality of the asphalt - decreases. It is therefore necessary to influence the improvement of regulations/standards internationally and on the domestic market to find opportunities to widen today's minimal amount of tests both on the number of different test methods as well as on the frequency of quality control. It is necessary to take into account the experience and results of the old methods of tests and quickly introduce modern, performance related tests.

Low temperature asphalt is becoming a reality in our practice. After a period of testing and the use of different methods of lowering the temperature of the asphalt production, the market established a method of lowering the temperature with foamed bitumen (the additive is water). The main manufacturers of equipment for the production of asphalt have developed procedures and equipment, which is built in in asphalt plants as standard. It is expected an increase in production of low temperature asphalt, mainly due to comprehensive benefits that this technology provides, i.e. healthier environment for workers in the asphalt industry, the reduction of greenhouse gas emissions and the reduction in energy consumption. The latter consistently applying this technology also means a reduction of total cost of production. In some countries (USA, Norway, France, ...) a systematic approach to the use of low-temperature asphalt is adopted, so that this asphalt takes a significant percentage in the total production of asphalt mixtures. The primary purpose of promoting this technology in Norway is the contribution to the health of workers, and the State on the basis of an agreement with the trade unions and the state administration for each ton of this product contributes 4 Euros.

Asphalt with rubber is a technology by which the recycled rubber from old tires is used in asphalt mixtures. The most widely used is the so-called wet process, after which the recycled rubber granules in a 20% share are mixed in bitumen. This binder is a competitive product to polymer modified bitumen, because the modification with rubber granulate offers a wide range of temperature resistance of asphalt mixtures. Use of rubber contributes to resistance to dynamic loading and to adhesion. Experience from neighbouring countries Italy, Austria and Germany, which have also been confirmed in a test field on the motorway Divača - Kozina in 2013, are positive, although all of the answers to our questions are not yet known. Environmental effects are still not fully known, also the equivalent bearing capacity of the product in smaller embedded layer thickness is questionable. But the contribution of this asphalt in reducing the noise is undisputed. Since noise is one of the biggest environmental problems in connection with the traffic, the development of this technology is expected mainly in this direction.

 It is necessary to approximate the design and construction of asphalt pavements to Guidelines to sustainable construction. It is necessary to take into account all aspects of sustainable development (LCCA, assessment of environmental impacts, etc.). It is proposed to produce the adequate technical guideline, which will be the foundation for the introduction of optimal processes and materials in practice. It is also necessary to redefine the design period in new construction and rehabilitation to enable the competitiveness of the entire spectrum of existing technologies. Cited knowledge and technical guidelines should be introduced in legislation on green public procurement and thus new standards and implementation of new practices in the field of design, construction and maintenance of roads in particular, should be set.

 In connection with the sustainable development of the asphalt industry in Slovenia is also a maintenance system of state roads. Annual cuts in funding for maintenance are directly reflected in the condition of the roads. In 2013 we are approaching the assessment that over 60% of national roads are in poor and very poor condition with extremely negative trend. In the period 1995 - 2010 we have built a motorway system that works. Its traffic (AADT of 40,000 vehicles), and traffic loads (an average of about 8,000 trucks per day) on the network, on average, have two, three or four times exceeded the predictions from the time of planning. Although the traffic is reducing, the traffic load is still at a very high level. It is therefore essential to ensure the reinforcements of motorway pavement structures on time. When deep deformations occur, which is already happening on some sections, the cost of rehabilitation increases several times. Because of that we cannot understand the drastic reduction in funding for the maintenance of national road network and lack of investment in motorways.

In addition to road infrastructure for the long-term sustainability in the transport sector it is necessarily to systematically regulate all other transport sectors as well. The Programme of development of transport infrastructure until 2020 (2030), which is currently being prepared on MzIP in collaboration with a number of contractors, should bring all transport sectors to the common denominator and give - with the operational investment plan until 2020 - guidelines for future development in the field of transportation. Beside that the Programme of development, which must be prepared and adopted in 2014, will pay particular attention to the maintenance of existing infrastructure, which has – even more in difficult economic conditions - get special significance. Every investment in infrastructure multiplies by a factor of 2.5 to 3, which has repeatedly been proven and which also admits the European Union. The construction industry in Slovenia strives for sustainable planning with even yearly investments, which will allow adjustment, operation and development.

For the future of asphalt and asphalt industry it is very important to have a positive opinion of the general public and the positive image of the profession among people. This is a positive only if we succeed in improving public understanding of the actual situation in our industry. We emphasize too little or not at all the positive aspects and effects that asphalt pavements bring. We must realize that asphalt as the most used material in an urban environment, facilitates communication between people, less dust, smooth running, lower fuel consumption, noise reductions, etc.. It is essential that the communication and exchange of information takes place at all levels and among all stakeholders. Asphalt roads are built in order to serve users and therefore we want to make the public well informed and aware that the asphalt continues to be the optimal choice for today and tomorrow.

Slovenian Asphalt Pavement Association

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