Projekt BVFF - publicerade   BVFF nummer:  2012-074 Projekttitel  Improving the quality of cold mix asphalt Projektledare/Kontaktperson  Niki Kringos Telefon  08-7908700 Utförarorganisation  KTH Medutförare  - Bakgrund  With 90% of the total European road network having an asphalt surface or incorporating recycled asphalt concrete in one of its base layers, the annual production of asphalt concrete in Europe is well over 300 million tonnes. It is therefore fair to state that asphalt concrete plays a significant role in the economic viability and international position of the European pavement industry. Associated with the production of asphalt is, unfortunately, also a cost to the environment via energy usage and Green House Gas emissions. A significant contribution to reduce the environmental impact, but preserving the driving comfort and durability associated with asphalt pavements, is to go to cold mix technology. Not having to heat the material components to high temperatures also has an additional advantage for the workers, who are no longer exposed to fumes during the paving of the asphalt. The downside of not heating the materials is, however, that the traditional HMA mixing technologies no longer apply, the laying process must be altered to ensure sufficient workability and additional technology is required to ensure the long-term quality of the mixture. In this project a fundamental chemo-mechanical study will be performed that will investigate adhesive and cohesive strength of asphalt after emulsification techniques. The effect of the emulsion’s breaking point, the enclosure of water, proper mixture of the minerals within the asphalt and bitumen coalescence will all be investigated. It is also aimed that within the project a new test methodology will be developed to measure coalescence of bitumen. In addition to the laboratory study, numerical modeling to model the observed phenomena and a larger mechanical (field) test to validate the quality of the developed optimized cold mix asphalt will also be included in the project. Sammanfattning  The most noted problems of applying cold mix asphalt on a large scale are the insufficient and unpredictable long-term performance, an added complexity in the design, production and maintenance of cold mix pavements and complex cost-benefit relationships. The purpose of this project is to improve the applicability of cold mix asphalt in Sweden by improving cold mix asphalts’ long-term performance, by making recommendation for appropriate laboratory and field performance tests for cold asphalt mixes and by defining the optimum cost-benefit relationship from a combined environmental and economical perspective. The project consists of four Parts: Part 1 is focusing on improved long-term performance and enhanced performance predictability, Part 2 is developing laboratory and field performance tests, Part 3 is formulating the optimum cost-benefit relationship and in Part 4 the Cold Asphalt Road Map will be developed. From this project many results are expected, among which detailed guidelines for enhanced properties of cold asphalt mixtures, a new fundamental laboratory test procedure to assess long term performance of cold asphalt mixtures, and combined environmental-economical cost-benefit relationships that will assist in the future decision making process. In the project, 2 PhD candidates will be appointed, even though they both will work in parallel on the project it is anticipated that the first PhD will focus on Part 1 and the laboratory part of Part 2, and the second PhD will focus on the field part of Part 2 and Part 3. Both will contribute to Part 4 of the project. In addition to the research and supervision team, a user-producer reference group will be formed at the start of the project. Collectively, the research team and the user-producer group represent the material producers, construction industry, policy, infrastructure owner and scientific point of view. As such this project will take into account the various point of views that need to be considered, while minimizing the gap to bringing the project results to implementation. Förväntat resultat  In addition to a significant enhanced insight into the current challenges that prevent larger scale implementation of cold mix asphalt technology and the associated scientific publications, the following results are expected: - guidelines for enhanced properties of cold asphalt mixtures; - mechanics based models to predict long-term cold mix performance; - a new fundamental laboratory test procedure to assess the long-term performance of cold asphalt mixtures; - combined environmental and economical cost-benefit relationships for cold mix asphalt to assist in the future decision making process; - a detailed road-map stipulating what future steps must be taken for successful implementation of cold mix asphalts in Sweden. Plan för resultatspridning och implementering  To ensure that the results of the project will move towards application in a rather short time-frame, the following steps will be taken: - A user/producer reference group will be formed at the start of the project. In this group, representatives of the associated industries, policy makers, technologists and R&D experts will be invited. Three times a year, a detailed presentation will be given to this this reference group; - During the project, it is anticipated that several publications will be submitted on the research to both international and national events, important for the pavement engineering community; - Self-standing modules will be developed which can be readily used for implementation in a practical engineering setting, thus ensuring the application of the developed knowledge into modern-day engineering practise. Each module will be accompanied by an appropriate case-study to increase its usability; - To advertise the results of the project and to demonstrate its application, an international workshop will be organized at the end of the project in which the results will be presented and in which an international group will be formed for the continuation of the research via applications of grants in a European and international framework, thus ensuring the continuation and monitoring of the developments of the project. Tidsramar  -