One of the most common distresses observed in asphalt pavements is cracking, normally caused by the combination of thermal gradients, traffic loads and the ageing of the asphalt binder. Nothing can be done to avoid the first two causes, but the third one can be improved by studying the binder behaviour. With time, asphalt binders undergo what it is a called ageing, which essentially increases the stiffness of the material. Once the binder is too stiff, traffic loads and thermal gradients produce cracks in the mixture, which allows rainfall water to penetrate in the pavement and further damaging the pavement structure with time. For that reason, many test procedures try to characterize the asphalt binders to help avoid or delay this kind of problems. The main property of the binder that can be related with in-field cracking of the asphalt mixture is ductility at service temperatures. This property is measured using an apparatus that pulls apart a sample of binder at a constant speed until the specimen breaks (ASTM D 113 and UNE EN 13589). The ductility is normally measured as the distance the specimen can elongate before breaking. However, when ductile and/or modified binders are tested the elongation can be so high that the apparatus is not long enough to perform the test successfully. The aim of this project is to develop a new test procedure that is able to measure successfully the ductility of wide range of types of asphalt binders at a wide range of temperatures. This new procedure will help stablish the range of service temperatures of the binder according to the environmental conditions, in similar manner the SUPERPAVE procedure does but with the main advantage of using only one test and requiring a much simpler test equipment. A new test geometry will be proposed based on an existing test procedure that has had great success on characterizing cracking behaviour on asphalt mixtures, the Fenix test. This new procedure will be able to show differences between ductile and/or modified binders, covering the gap left by the existing ductility related procedures. The better characterization of ductile binders will help improve the design of asphalt mixtures. This should translate in higher durability of mixtures in the field, which should suppose an important reduction in conservation costs, consumption of raw materials and emission of greenhouse gases. This research project addresses the challenge number 4: Sustainable, smart and integrated transport of the 2018 call for I+D+i Research Challenges projects of the Spanish Ministry of Science, Innovation and Universities. Specifically, this project is contained in the point 1 that promotes the research and application of new advanced transport materials, pavements and infrastructures, including the development of technologies related to the circular economy (eco-design, re-use, recuperation, re-fabrication and recycling). The development of a new test procedure to optimize the binder selection for the mixture taking into account the environmental conditions, as stated in this project, will help increase the service life of road pavements, minimizing conservation operations and reducing the consumption of raw materials and the emission of greenhouse gases.
Plan Estatal de Investigación Científica y Técnica y de Innovación 2017-2020
Programa Estatal de I+D+i Orientada a los Retos de la Sociedad