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This paper analyses, both experimentally and numerically, the transport of chloride ions inside concrete. The samples are made from either 100% Natural Aggregates (NA) or 100% Recycled Concrete Aggregates (RCA). The goal of this research is to quantify the loss of durability of Recycled Aggregates Concrete (RAC) with respect to Natural Aggregates Concrete (NAC), possibly promoting their use in long-term building. The experimental campaign focused on evaluation of transfer properties of concrete: water absorption, retention curves, intrinsic permeability, chloride diffusion under steady and unsteady state and conduction experiments were performed. The results depict that RAC tends to have higher exchange rates with the environment than NAC, mainly due to the increased paste content from the recycled aggregates., Academic Journal of Civil Engineering, Vol 40 No 2 (2022): Special Issue - NoMaD 2022

Decreasing CO2 emissions and preserving natural resources are necessary to the well-being of our civilisations. In the construction industry, recycling old concrete members could be part of the solution to reach theses objectives. Recycled Concrete Aggregates (RCA), obtained by crushing of demolished concrete structures, can substitute the Natural Aggregates (NA) inside the so-called Recycled Aggregates Concrete (RAC).The durability of RAC is not guaranteed in the current state of research. RCA are indeed composed of natural aggregates partially embedded in an adherent mortar paste, increasing the porosity and water absorption of RAC. This research aims to better predict the influence of RCA on chloride ions ingress inside concrete. It started with an experimental phase where multiple experiments have been performed to determine the transfer properties and the chloride ions diffusion coefficients of a mortar paste and concretes made from NA or 100% RCA. In this context, the microstructure of the RCA influences deeply the permeability, water content distribution and chloride ingress. Therefore, these properties must be included into a numerical model that integrates the microstructural information in a proper way. A numerical homogenization technique, based on the Finite Element square (FE2 ) method [5, 13], is implemented into a coupled multiscale model of water flows and advection/diffusion of chlorides in saturated concrete, in order to model the complex flow behaviour encountered.

As part of a CIFRE agreement with the company ARTHUR DUPUY®, this research is embedded in a current societal issue which is to favour the use of public transportation at the expense of the individual car. The thesis that we defend is that scent diffusion in public transport is one of the solutions that will contribute to achieving this goal. In a first study, we were interested in better understanding the cognitive processes at play in auditory-olfactory crossmodal interactions. Indeed, it has been shown that noise and odours have a negative impact on the comfort and well-being of transportation users. In a second study, we wished to study the potential existence of certain beliefs about fragrances and their use that could jeopardise the sustainability of a scent diffusion project: the perceived dangerousness of scents and the inference of manipulation intent. In a third study, we evaluated the effects of the diffusion of an ambient scent in a tramway carriage on user experience. Our results suggest that (1) it is possible to take care of olfactory annoyances independently of hearing annoyances (2) synthetic scents are perceived as dangerous to health (3) the diffusion of an ambient scent in a tramway carriage improves user comfort and decreases the perception of olfactory annoyances. Beyond theoretical and experimental contributions, this transdisciplinary work at the crossroads of psychology, marketing and transport, reveals that the study of the effects of the diffusion of an ambient scent in public transport on user experience is still in its infancy. New research is still needed to better understand the impact of this marketing technique and, ultimately, to exploit its full potential for the benefit of users.; Dans le cadre d’une convention CIFRE avec la société ARTHUR DUPUY®, cette recherche s’ancre dans une problématique sociétale actuelle qui est de favoriser l’utilisation des transports en commun aux dépens de l’automobile individuelle. La thèse que nous défendons est que la diffusion d’un parfum d’ambiance dans ces lieux est l’une des solutions qui contribuera à y parvenir. Dans une première partie, nous nous sommes intéressés à mieux comprendre les processus cognitifs en jeu dans les interactions crossmodales audio-olfactives. En effet, il a été montré que le bruit et l’odeur avait un impact négatif sur le confort et le bien-être des usagers des transports. Dans une deuxième partie, nous avons souhaité étudier l’existence potentielle de certaines croyances envers les parfums et leur utilisation qui pourraient mettre en péril la mise en place d’un projet de diffusion : la dangerosité perçue des parfums et l’inférence d’intention de manipulation. Dans une troisième partie, nous avons évalué les effets de la diffusion d’un parfum d’ambiance dans une rame de tramway de la ville de Montpellier, sur l’expérience des usagers. Nos résultats suggèrent que : (1) il est possible d’adresser les nuisances olfactives indépendamment des nuisances auditives, (2) les parfums synthétiques sont perçus comme dangereux pour la santé, et (3) la diffusion d’un parfum dans les rames d’un tramway permet d’améliorer le confort des usagers et de diminuer la perception des nuisances olfactives. Au-delà des apports théoriques et expérimentaux, ce travail transdisciplinaire à la croisée de la psychologie, du marketing et des transports, révèle que l’étude des effets de la diffusion d’un parfum d’ambiance dans les transports en commun sur l’expérience des usagers n’en est qu’à ses débuts. De nombreux travaux sont encore nécessaires afin de mieux comprendre scientifiquement l’impact de cette technique marketing et in fine, d’en exploiter tout son potentiel au service des usagers.

This publication is part of the proceedings of the Biot-Bažant Conference on Engineering Mechanics and Physics of Porous Materials, which took place virtually on June 1-3, 2021. It contains a one-page abstract and the video of the talk that was given at the conference.