Properties of Asphalt Mixtures with Multiple Recycled Asphalt Material

摘要

Asphalt recycling is a crucial part of end-of-life strategies for pavements which are for many years in operation. It fully respects the defined trends of European Union to become a non-waste society with challenging targets for the whole industry. In case of pavement engineering recycling technologies are well know and have been developed for several decades covering cold ad hot solutions depending on the preferences of particular markets. The question presently is how to deal with pavements once recycled. Since such material will not last in the pavement forever it is important to understand if it can be used more efficiently than like aggregates. In this respect solutions have been searched both in cold and hot recycling adding at least 30 % of once recycled material in new asphalt mixtures. In parallel it was analyzed what kind of activity can be identified for these recycled asphalt materials. For the experimental study original reclaimed asphalt was used in a standard way for cold recycled mix using either bituminous emulsion or foamed bitumen. The mix was laboratory aged according to test protocol drafted for European market. Aged cold recycled asphalt material was crushed to simulate a second cold milling and gained granular material was again used as reclaimed asphalt in cold recycled mixes and in standard hot mix asphalt (HMA). Different binders were applied for HMA analyzing the effect of additives used. In case of cold recycled mix mainly the content of added binder was analyzed. For designed mixes mechanical and functional tests were performed to get a more complex understanding of the impact of multiple recycling on mix behaviour. From the perspective of functional testing mainly stiffness and crack behaviour was analyzed. The paper summarizes gained results and gives an overview of potentials related to multiple recycling of asphalt pavements including the influence of selected additives.