Prediction of the viscoelastic properties of an asphalt mixture: Micromechanical and experimental approaches(Article) [Prédiction des propriétés viscoélastiques des enrobés bitumineux Approches micromécaniques et expérimentales]

The asphalt mixtures are composed of aggregates and asphalt used in the construction of the majority of roads. In order to ensure the sustainability of the infrastructures, the evaluation of the quality and the performances of these materials are essential. In this context, several researches have been focused on the development of predictive models, often empirical ones, in order to deduce the viscoelastic properties of an asphalt mixture based on the properties of its constituents (binder and/or aggregate). In this context, we suggest a homogenization model based on the generalized self-consistent scheme (GSC) to predict the complex module of the asphalt concrete from the properties of its components. In the aim of the approach validation, different types of mixtures (hot and warm) made in the laboratory were tested. The results showed that one can predict the complex modulus of the different types of asphalt concretes for temperatures less than 20 °C. However, beyond this temperature, the precision of the model decreases. Besides, the comparison of the micromechanical model with the rheologic models in literature showed that the suggested model can be also relevant in terms of predictions as the considered models

Effect of Phase Change Materials (PCMs) on the hydration reaction and kinetic of PCM-mortars

International audienceThe Phase Change Materials (PCMs) are considered as an attractive way to reduce energy consumption thanks to their heat storage capacity. Their incorporation in the construction materials (gypsum, concrete) contribute to the reduction of the energy consumption of the building structures.Even though PCMs have shown their reliability from a thermal point of view, some drawbacks linked to their use were emphasized such as the loss of the compressive strength of the cementitious material with the addition of PCMs.This paper attempts to provide a possible explanation by the investigation of the hydration kinetic of PCM-mortars. The conventional semi-adiabatic Langavant test was adapted for this purpose. The results showed a lower heat released by the PCM-mortars compared to a control mortar as well as a delay in the hydration process with the addition of PCMs which may contribute to the loss of the compressive strength

Effect of Phase Change Materials on the hydration reaction and kinetic of PCM-mortars

International audienceThe Phase Change Materials are considered an attractive way to reduce energy consumption thanks to their heat storage capacity. Their incorporation in the construction materials allows the energy to be an integral part of the building structure. Even though PCMs have shown their reliability from a thermal point of view, some drawbacks linked to their use were emphasized such as the loss of the compressive strength of the PCM-material. This paper attempts to provide an explanation by the investigation of the hydration kinetic of PCM-mortars. The semi-adiabatic Langavant test was adapted to this case. The numerical Diffuse Element Method was used for the computation of the heat flux which is a compulsory step for the determination of the hydration degree. The results showed a lower heat released by the PCM mortars compared to a control mortar as well as a delay in the hydration progress with the addition of PCMs

Investigation expérimentale et modélisation multi-échelle des propriétés thermiques des bétons incorporant des Matériaux à Changement de Phase (MCPs)

National audienceRÉSUMÉ. L'utilisation des matériaux à changement de phase (MCP) dans le domaine des bâtiments est une solution attractive contribuant à la réduction de la consommation d'énergie ainsi qu'à l'amélioration du confort thermique. Ce travail est consacré à l'étude des propriétés thermiques des MCP et des bétons modifiés (chaleur spécifique, conductivité thermique). Des techniques expérimentales ont été mises en jeu telles que la calorimétrie différentielle à balayage (DSC), le Hot Disk et le laser flash. Une modélisation micro-macro est aussi présentée afin de prédire la conductivité thermique des bétons-MCP en se basant sur quelques schémas d'homogénéisation classiques. ABSTRACT. The use of Phase Change Materials (PCMs) in the building sector is an attractive solution contributing to the reduction of energy consumption as well as the improvement of the thermal comfort. This research is devoted to the study of thermal properties of PCMs and modified concrete (specific heat, thermal conductivity). Experimental techniques were used such as the Differential Scanning Calorimetry (DSC), the Hot Dish and the Laser Flash. Also, a micro-macro modelling is presented in order to predict the thermal conductivity of PCM-concrete using some classic homogenization schemes

Experimental and multi-scale analysis of the thermal properties of Portland cement concretes embedded vith microencapsulated Phase Change Materials (PCMs)

International audienceThe present research deals with the investigation of a Portland cement concrete modified with organic microencapsulated Phase Change Materials (PCMs) named Micronal DS 5001 X, using experimental and homogenization approaches. First, a laboratory characterization of the PCM smart materials was performed using different experimental techniques. Second, different PCM-concrete mixtures were manufactured with different amounts of PCM. The specific heat capacity of PCM-concrete was analyzed by differential scanning calorimetry technique whereas the thermal conductivity was measured by hot disk. In addition, PCM-concrete mixes were subjected to artificial ageing then their thermal properties were analyzed. Besides, a homogenization approach was carried in order to predict the thermal conductivity of the PCM-concrete mixes. The results highlighted an improvement of the heat storage capacity of the PCM-concrete with the addition of PCMs. Moreover, a good correlation was noticed between the experience and the homogenization method for the thermal conductivity prediction