First-year asphalt mixture results from a European in situ Ageing Consortium (EurIAC)

Ageing of asphalt pavements is an inevitable phenomenon that reduces the overall lifespan of the road net-work. Typically, this process is simulated in the lab, however several climatic factors are often overlooked in such simulations. To evaluate the ageing effects more realistically, a network of universities in six West-ern-European countries was established in the summer of 2023. This paper reports the first-year results of in situ climatic conditioning and its effect on a reference asphalt mixture. Asphalt slabs were assessed for their mechanical performance via indirect tensile strength and resilient modulus. The findings depict slight differences between the participating labs concerning these properties, with the majority of them pointing to slightly increased modulus values ascribed to ageing. The extent of mix properties changes, yet in the early stages of long-term ageing, is still insignificant. Finally, a moderate positive correlation was found between the two asphalt mixture properties which can collectively explain the regional differences across Europe in the near future. Correlations with the changes at the binder level will also be considered as well as the link-age to the climatic history, as additional results will become available over extended time intervals

Rheological, physicochemical, and microstructural properties of asphalt binder modified by fumed silica nanoparticles

Warm mix asphalt (WMA) is gaining increased attention in the asphalt paving industry as an eco-friendly and sustainable technology. WMA technologies are favorable in producing asphalt mixtures at temperatures 20–60 °C lower in comparison to conventional hot mix asphalt. This saves non-renewable fossil fuels, reduces energy consumption, and minimizes vapors and greenhouse gas emissions in the production, placement and conservation processes of asphalt mixtures. At the same time, this temperature reduction must not reduce the performance of asphalt pavements in-field. Low aging resistance, high moisture susceptibility, and low durability are generally seen as substantial drawbacks of WMA, which can lead to inferior pavement performance, and increased maintenance costs. This is partly due to the fact that low production temperature may increase the amount of water molecules trapped in the asphalt mixture. As a potential remedy, here we use fumed silica nanoparticles (FSN) have shown excellent potential in enhancing moisture and aging susceptibility of asphalt binders. In this study, asphalt binder modification by means of FSN was investigated, considering the effects of short-term and long-term aging on the rheological, thermal, and microstructural binder properties. This research paves the way for optimizing WMA by nanoparticles to present enhanced green asphalt technology