André-Gilles Dumont | EPFL Graph Search

André-Gilles Dumont est né en 1951 à la Brévine (NE). Il obtient en 1976 le diplôme d'ingénieur civil de l'EPFL.

Jusqu'en 1979, il est collaborateur d'un bureau d'ingénieurs et dirige la construction de divers bâtiments. Il entre ensuite au Laboratoire des voies de circulation (LAVOC) où il va développer une méthodologie d'essais en vraie grandeur des superstructures routières. Cette activité sera poursuivie au niveau international au sein de deux groupes d'experts scientifiques de l'OCDE.

Parallèlement au développement du LAVOC et à l'exécution de nombreux mandats pour des tiers, il est l'auteur de plusieurs recherches dans le domaine des matériaux granulaires et des bitumineux modifiés par des polymères.

En Suisse, il assume dès 1985 la présidence de la commission Technologie des matériaux de l'Union des professionnels suisses de la route puis, dès 1990, celle de la commission de coordination Exécution et entretien.

Depuis 1991, il est professeur et dirige le LAVOC. Il enseigne aux étudiants du génie civil et du génie rural, d'une part le tracé des voies de circulation et, d'autre part la construction et l'entretien des superstructures routières. Il mène également des recherches dans le domaine des propriétés des matériaux hydrocarbonés et de la modélisation des chaussées, comme dans celui de l'utilisation de la CAO pour l'élaboration des projets routiers et la prise en compte des facteurs environnementaux.

A framework for characterizing RAP clustering in asphalt concrete mixtures

Sara Bressi, André-Gilles Dumont, Manfred Partl, Michel Pittet

Recycled Asphalt Pavement (RAP) is commonly used in asphalt for road rehabilitation or new constructions. Nevertheless, some physical and chemical phenomena that occur during production, laying and compaction of mixtures containing RAP are not yet completely explored. One of the main aspects is represented by the interaction between the aged bitumen from RAP and the virgin bitumen added to the mixture as well as the creation of clusters among small-size RAP particles. In this paper several combinations of mixtures are studied, varying the amount of RAP, the type of new binder and the testing temperature in order to obtain a suitable data set for the development of a framework for characterizing clustering of RAP during mixing hot recycled asphalt concrete based on the parameters mentioned above. For analyzing the experiments, the Response Surface Methodology (RSM) was applied. The set of points (combinations tested) for calibration of the models was selected using the Dohelert network, which is a design optimization strategy that allows the effective estimation of the models coefficients. The agglomeration of RAP particles is investigated for all virgin binders used and for all the percentages of RAP. It was shown that the quantity and the quality of virgin aggregates play a significant role in the clusters formation. Moreover, this experimental work suggested that revised formula for the calculation of the bitumen film thickness is needed, in order to include the combined effect of bitumen penetration and fabrication temperature. (C) 2015 Elsevier Ltd. All rights reserved.

Elsevier Sci Ltd2016

A new laboratory methodology for optimization of mixture design of asphalt concrete containing reclaimed asphalt pavement material

Sara Bressi, André-Gilles Dumont, Manfred Partl

The reduction of virgin bitumen added to asphalt mixtures containing Reclaimed Asphalt Pavement (RAP) is based on the typical assumption that all the aged binder function in the same way as the virgin binder. However, recent studies conducted by the authors for a specific case show that a blend or mobilization of RAP binder are negligible. The aged bitumen becomes softer acting as glue facilitating cluster formation between small-size RAP particles. The reduction of small-size particles causes changes in the target grading curve and in the voids-fill, affecting the compactability of RAP mixtures. Therefore the target grading curve of RAP mixtures needs to be readjusted, using different proportions of virgin aggregates and taking into account the cluster phenomenon. The objective of this paper is to develop a new mix design approach for RAP mixtures, taking into account the cluster phenomenon and the contribution of the aged bitumen in the compactability. The virgin aggregates, filler and RAP are investigated and individually included in the calculation. 3D images of the virgin aggregates allowed the determination of new surface area factors; the concept of critical filler concentration led to the definition of the minimum bitumen quantity required to maintain the mastic in a diluted state and fill the voids. A RAP clustering model was introduced to predict the agglomeration of small-size RAP particles. The readjustment of the target grading curve was analytically calculated, allowing the correct estimation of the amount of virgin bitumen to be added to asphalt mixtures. Finally, a first verification of the entire process was carried out performing laboratory tests. These promising results enable the challenge of a new mix design optimization for HMA with high RAP content to be addressed.

Springer Verlag2016

An advanced methodology for the mix design optimization of hot mix asphalt

Sara Bressi, André-Gilles Dumont, Manfred Partl

The bitumen quantity to add to asphalt mixtures depends on the surfaces of aggregates and filler to be coated. The formulas currently available in the literature have limitations such as considering all the fillers with the same specific surface or the aggregates with spherical or cubical shapes. This paper aims to define an analytical approach for the determination of the optimal dosage of bitumen in HMA proposing new methodologies to go a step further in the resolution of the above mentioned approximations. Indeed, new surface area factors were calculated to determine the aggregates surface considering their real shapes and volumes. Afterwards, the authors proposed a detailed characterization of two types of fillers and the critical filler concentration, introduced by Faheem and Bahia, was used to calculate the minimum amount of bitumen for maintaining the mastic in a diluted state and filling the voids in the mixtures. Finally, a verification of the formula developed was carried out with specific laboratory tests. These results allow the challenge of revising the method of calculating the specific surface of the aggregates and filler to be addressed with the final goal to include them in a new mix design optimization for HMA. (C) 2016 Elsevier Ltd. All rights reserved.

Elsevier Sci Ltd2016

A new laboratory methodology for optimization of mixture design of asphalt concrete containing reclaimed asphalt pavement material

Sara Bressi, André-Gilles Dumont, Manfred Partl

Springer Verlag2016