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

Recommendation of RILEM TC 237-SIB on complex Poisson’s ratio characterization of bituminous mixtures

none7siThis recommendation describes how to characterize the isotropic three-dimensional linear viscoelastic behaviour of bituminous mixtures through the simultaneous measurement of the complex Young’s modulus (E ) and the complex Poisson’s ratio (m ). The guidelines given herein are based on the results of a RILEM round robin test organized by the RILEM Technical Committee 237-SIB ‘‘Testing and characterization of sustainable innovative bituminous materials and systems’’ and focus on the testing procedure, measurement setup, data analysis and presentation of results. Indications for the preparation of a tests report are also given.restrictedGraziani, A; Di Benedetto, H.; Perraton, D.; Sauzéat, C.; Hofko, B.; Poulikakos, L.D.; Pouget, S.Graziani, Andrea; Di Benedetto, H.; Perraton, D.; Sauzéat, C.; Hofko, B.; Poulikakos, L. D.; Pouget, S

Recommendations of RILEM TC 252-CMB: relationship between laboratory short-term aging and performance of asphalt binder

This recommendation reports on the effect of the Rolling Thin Film Oven Test (RTFOT) aging temperature on chemo-mechanical properties of asphalt binders for Warm Mix Asphalts. The RTFOT testing temperature should ideally replicate physical and chemical short-term aging of asphalt mixtures. The relevance of this was investigated in light of the increased use of warm mix asphalt technologies. The recommendations are based on round robin experiments performed by nine participating laboratories and consisting of a series of tests including experimental results on penetration, softening point temperature, Fourier Transform Infrared Spectroscopy and Dynamic Shear Rheology. The results indicate that the current RTFOT aging temperature does not replicate the aging in the mixture. For this reason, the TC recommends the selection of appropriate RTFOT aging temperatures in order to simulate binder aging as a result of various mixing technologies. The sulfoxide index is proposed as a measure of oxidative short term RTFOT aging

Effect of short-term ageing temperature on bitumen properties

© 2017 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group. Properties of asphalt mixtures after ageing are fundamental parameters in determining long-term performance (e.g. durability) of these materials. With increasing popularity of reduced temperature mixtures, such as warm-mix asphalt, WMA, the question remains how a reduction in short-term ageing affects the properties after long-term ageing of bituminous materials. This paper aims to improve our understanding of the effect of asphalt manufacturing temperature on ageing and the resulting mechanical properties of bituminous binder by studying the effect of short- and long-term ageing of different bitumen samples as a function of short-term ageing temperatures. For this purpose, round robin experiments were conducted within the RILEM technical committee (TC) 252 chemo-mechanical characterisation of bituminous materials by 10 laboratories from 5 countries using four binders of the same grade (70/100 pen) from different crude sources. The short-term ageing was carried out using the standard procedure for rolling thin film oven test (RTFOT), but varying the temperatures. Long-term ageing was carried out using the standard procedure for pressure aging vessel (PAV) in addition to RTFOT. For the mechanical characterisation, rheological data were determined by using the dynamic shear rheometer (DSR) and conventional tests, with needle penetration and softening point using the ring and ball method. The results show that although different short-term ageing temperatures showed a significant difference in the mechanical properties of the binders, these differences vanished after long-term ageing with PAV

Tracking aging of bitumen and its saturate, aromatic, resin, and asphaltene fractions using high-field fourier transform ion cyclotron resonance mass spectrometry.

Bitumen is a widely used material, but its aging behavior is only understood at a macroscopic level as hardening and embrittlement over time. To assess bitumen aging behavior in the long run, the pressure aging vessel (PAV) testing procedure was developed. However, this procedure including high-pressure and high-temperature oxidation of the bitumen has not yet been understood on a molecular level. Here, a bitumen sample and its SARA fractions, i.e., saturates, aromatics, resins, and asphaltenes, were investigated in comparison with their aged samples to study changes of their chemical compositions. Negative electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry [ESI(-)] FT-ICR-MS was used to analyze samples. The effect of aging was characterized using the aromaticity equivalent (X-c, double bond equivalent (DBE), and van Krevelen plots. It was found that aging induces reduction of condensed aromatic compounds to alicyclic and open chain aliphatic compounds, while small aromatic compounds have been found to be relatively stable (or altered only slightly). Abundant alterations were detected in unaged bitumen. These changes can be assigned to resins and asphaltenes as compared to saturates and aromatics. Overall, alterations of highly condensed compounds were found to be related to aging. Furthermore, molecular series of CHO, CHNO, and CHOS fragments were more susceptible to oxygenation in bitumen, aromatics, resins, and asphaltenes as compared to saturates. In addition, molecular changes in asphaltenes showed a significant difference from classical assessment with high content of condensed aromatic compounds. Rather, the most abundant compounds in asphaltenes appear to be more saturated and apolar