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In recent years, the use of light-coloured pavements has been encouraged internationally for urban design. In particular, colour is a lever that allows the designer to meet an objective of urban roads: the sharing of space, for uses and users. It is also a key factor for pavements in environmental and monumental contexts, where the aesthetics and appearance of the finished layer are essential characteristics.The Pavements and Lighting working group has established a large library of current and innovative urban pavements available on the French market. The colour of these surfaces is notably part of the assessed properties. The objective of this study is to have a tool and an analysis method to understand the development of a project and its evolution according to the effects of colour change.A set of 30 pairs of samples were characterised in their initial state and after 30 months of natural ageing in outdoor conditions, i.e. exposed to rain and sun. It included pavements of several categories: asphalt concrete (bituminous or synthetic binder), mastic asphalt, poured and precast cement concrete. The colour of each sample was measured using three different processes (devices and methods).The results provide a first overview of the colorimetric coordinates per pavement family and show a wide range of achievable colorimetric characteristics. The impact of natural ageing on the colour of the road surface is studied by the comparison of the original with the 30 months measurements. The obtained results highlighted that not all pavements evolve in the same way, depending on their mixture and their finishing stage. Usually, the asphaltic pavements (concrete and mastic) tend to evolve more than the cement concrete samples (poured and precast). The colour of a pavement without surface treatment changes more than a treated one, as well as when dark aggregates are used. The same is true when the binder is synthetic, but it seems that the use of TiO2 in synthetic asphalt pavements reduces the colour evolution.

Dans un environnement urbain, les pièges à carbone naturels et artificiels peuvent être des leviers intéressants pour tendre vers la neutralité carbone d’un territoire. Cette étude s’intéresse au potentiel de piégeage de CO2 d’un stock de granulats recyclés, fabriqués sur une plateforme de recyclage à partir de déchets inertes du BTP, entre deux campagnes de concassage. Grâce au développement d’une cellule de carbonatation naturelle et d’une cellule de diffusion de O2 en laboratoire, la quantité de CO2 piégé par un stock de 2000 m3 pendant 4 mois est estimée à plus de 630 kg, soit 0,2 kg de CO2/t de GR en stock. Cette faible valeur montre que même si le potentiel de piégeage de CO2 à l’échelle du grain est estimé à 23 kgCO2/t de GR, la capacité réelle d’un stock de GR à en piéger en condition atmosphérique est très dépendante du process de fabrication, du stockage sur plateforme et des conditions météorologiques., Academic Journal of Civil Engineering, Vol 40 No 1 (2022): Special Issue - RUGC 2022

Street lighting ensures visibility and legibility for road users. In this paper, performances of the lighting installation of two road sections with different type of road surface are measured in accordance with guidelines and road lighting standards. Then, the calculation of the visibility level of a target according to the Adrian’s model is included considering the light reflections on the road. We compare the results obtained for each section with and without considering the light reflections and conclude that there is an incidence of the nature of the road surface on the target luminance. However, the effect on the visibility level of the target is not so straightforward. This depends on whether it is close to the visibility threshold, and it is therefore important to consider the reflective properties of the road surface. Moreover, we see that the visibility level provides us more information than the classical descriptors. The same luminance distribution for two pavement/lighting couples does not necessarily lead to the same distribution in terms of target visibility. It seems necessary to us to reinstate the visibility level in the performance criteria defined by the standard because it would act as a local descriptor of the performance of the pavement/lighting combination and would thus make it possible to avoid safety problems.