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

A conditioning method to evaluate moisture influence on the durability of asphalt mixture materials

Over the years, researchers have developed many laboratory methods for conditioning and evaluating the moisture damage of asphalt mixtures. Most of the tests do not fully simulate field conditions and the evaluation criterion does not always predict the long-term susceptibility to moisture damage. This paper aims to present a comprehensive conditioning and evaluation method that simulates field conditions to assess the durability of bituminous layers against moisture damage. The equipment consists of a system applying a cyclic load on samples in which water can be forced through. The assessment procedure is based on the indirect tensile strength test after the conditioning method, from which the concept of the Damage Rate as an indicator for classifying the durability of mixtures against moisture damage, was developed. The method would allow asphalt practitioners to evaluate the mixture for susceptibility to moisture on a routine basis