Showing papers by "Emmanuel Chailleux published in 2017"

Source dependency of rheological and surface characteristics of bio-modified asphalts

Abstract: Asphalt industry has been looking to reduce their dependence on petroleum-based binders and apply non-petroleum binders as partial or full replacement for asphalt binders. This motivated several at...

Linear viscoelastic properties of high reclaimed asphalt content mixes with biobinders

Abstract: The use of high Reclaimed Asphalt (RA) content mixtures together with binders produced from renewable resources (biobinders) is one of the current challenges in pavement engineering research. On the one hand, RA has been used for decades, but there are still some concerns about its performance, especially when high contents are used (>30%). On the other hand, biobinders are relatively new materials, which have to be deeply characterised and studied in order to develop good practices for their use. In this paper, linear viscoelastic properties of biobinders and bio-mixtures manufactured with high RA content and biobinders are analysed and discussed. High-modulus mixtures with 50% RA were selected for the mix design. Binders and mixtures were tested over a wide range of asphalt service temperatures and frequencies by means of Dynamic Shear Rheometer and two-point bending tests, respectively. Results show that biobinders have an important effect on mixtures behaviour. However, no direct links between their l...

Molecular structure evolution of asphaltite-modified bitumens during ageing; Comparisons with equivalent petroleum bitumens

Abstract: This work focuses on the molecular structure evolution of asphaltite-modified paving bitumens during ageing. In order to quantify the effect of ageing on the molecular weight distribution (MWD) of bitumens, a new parameter, called hereafter the ageing molecular-distribution shift (AMDS), is introduced. The molecular evolutions of asphaltite-modified bitumens during aging are compared with the molecular evolutions of pure petroleum bitumens of equivalent grade. The results based on AMDS confirm previous research showing that the asphaltite attenuates the ageing and, compared to hard petroleum bitumens produced in refinery, the asphaltite-modified bitumens present a better ageing performance. The AMDS parameter reveals appropriate for the evaluation of evolutions due to ageing.

Evaluation of bio-materials’ rejuvenating effect on binders for high-reclaimed asphalt content mixtures

Abstract: The interest in using bio-materials in pavement engineering has grown significantly over the last decades due to environmental concerns about the use of non-recoverable natural resources. In this paper, bio-materials are used together with Reclaimed Asphalt (RA) to restore some of the properties of the aged bitumen present in mixtures with high RA content. For this purpose, two bio-materials are studied and compared to conventional and polymer modified bitumens. Blends of these materials with RA bitumen were produced and studied to simulate a 50% RA mixture. The rejuvenating effect of the two bio-materials on RA has been assessed and compared with the effect of the conventional binders. Apparent Molecular Weight Distribution of the samples (obtained by the ?-method) and different rheological parameters were used for this purpose. Results revealed the power of bio-materials to rejuvenate RA bitumen, showing their capability to be used as fresh binders in high-RA content mixtures.

Bitumen emulsion destabilization kinetics: importance of the crystallized wax content

Abstract: We study the kinetics of bitumen emulsion destabilization after the addition of sodium hydroxide (NaOH) using macroscopic observations and rheology. Destabilization occurs in a two-step process: first, emulsion flocculates, forming a percolated network of contacting drops, and then coalescence provokes the irreversible connection of bitumen drops, leading to a bitumen continuous network that further relaxes the shape. We show that the destabilization kinetics exhibits a rheological easily identifiable signature allowing reproducible and accurate measurement of the connection/coalescence time trc (which corresponds to the time, determined by rheology, required to form the network made of drops connected by nonrelaxed coalescence). Using this powerful tool, we show that, even if viscosity is thought to govern the shape relaxation of the connected network it does not determine the connection kinetics. Indeed, emulsions with similar rheological behaviors exhibit very different destabilization times. Instead, ...