Projekt BVFF - publicerade   BVFF nummer:  2018:2-09 Projekttitel  Long-term structural integrity of asphalt under combined mechanical and environmental loading Projektledare/Kontaktperson  Denis Jelagin (KTH) Telefon  087908698 Utförarorganisation  KTH Medutförare  PEAB VTI Bakgrund  A major obstacle to implementation of new materials in road construction is the absence of reliable tools to quantify the effects of material design parameters on asphalts long-term structural integrity, i.e. its ability to withstand traffic & environmental loads through design life. Environmental loads (i.e. temperature, moisture, de-icing agents, etc.) may affect profoundly asphalt distress accumulation with respect to cracking and rutting. Presently, there are, however, no accepted experimental and/or modelling tools allowing quantifying asphalts resistance to a combined action of environmental and mechanical loading; in particular, with respect to asphalt cracking under combined thermal and mechanical cycles and in presence of water. The goal of this project is to conduct a doctoral study at KTH on developing experimental and modeling framework to evaluate the long-term resistance of asphalt mixtures to combined mechanical and environmental loads. Expected project outcomes are test methods, conditioning protocols and models explicitly capturing the effects of mechanical and environmental loading on asphalt structural integrity. It is anticipated that experimental/modelling tools developed under the project will be instrumental in implementation of novel and environmentally friendly materials in road construction. The project outcomes will also be used to incorporate environmental loads into asphalt layer performance prediction models available in ERA Pave design tool. Sammanfattning  The project seeks to determine, quantify and model the relationship between the asphalt mixture parameters and its resistance to combined environmental and mechanical loads from a performance-oriented engineering point of view. The focus will be on fracture-related failure modes, i.e. asphalt fatigue cracking, raveling, aggregate loss due to adhesive/cohesive failures at the surface. The project aims to develop new test methods, conditioning protocols and models explicitly capturing the effects of mechanical and environmental loading on asphalts degradation. Project results will be instrumental in implementation of novel materials in road construction and will allow incorporating environmental loads into asphalt layer performance prediction Förväntat resultat  In addition to the theoretical and experimental insight to the link between asphalts material design and its resistance to structural integrity loss in the field, the project’s main outcomes will be as follows: - New test methods and conditioning protocols adequately capturing the effects of combined mechanical and environmental loading on asphalt structural integrity. The critical combinations of mechanical and environmental loading will be identified based on multi-physics FE modelling of asphalt degradation processes. - Modeling toolset for scientists and engineers for evaluation of the asphalts structural integrity at mechanical and environmental loading for improved design and materials development. - Improved understanding of the relationship between asphalts internal structure and mechanical properties of its components and materials resistance to structural integrity loss in the field. - Basis for improved consulting of the building industry and road authorities in implementation of novel and environmentally friendly materials, e.g. marginal/recycled materials in road construction. - Physics-based framework allowing incorporating environmental loads into asphalt layer performance prediction models. Plan för resultatspridning och implementering  In order to ensure that the results of the project are communicated to the research community and to the users, the following steps will be taken: - A user reference group will be formed at the start of the project. The reference group will consist of representatives of the following authorities/companies: Trafikverket (Robert Karlsson), Skanska, NCC (Jonas Ekblad), Peab. Twice a year, a detailed presentation will be given to the reference group. - Results of the project will be published in several scientific papers and summarized in a PhD-thesis. - The results achieved in the project will also be presented at SBU and Road2Science events - Results will be as well presented in national and international conferences. Tidsramar  The project will take 4 years and will start as soon as suitable doctoral candidate is recruited.