Advances in Multi-Physics and Multi-Scale Couplings in Geo-Environmental Mechanics
Abstract: Structures’ durability and their degradation mechanisms have received much interest fro... more Abstract: Structures’ durability and their degradation mechanisms have received much interest from the scientific community and project owners. Cementitious materials are the most common building materials. They have a complex microstructure with a highly heterogeneous and random character of their mechanical and physical properties. Various processes affect their properties: chemical, such as cement hydration, and physical, such as heat and moisture exchange. The latter, which relate to variations in the water content and its distribution in the material, have an important influence on the global behavior of cementitious materials. The process of convective drying is a commonly encountered solicitation in the Civil Engineering field. It can be either natural, such as drying of concrete structural elements, or forced, such as drying in a research laboratory during the sample preparation and characterization.
AbstractTwo types of concrete mixtures (Concrete A and Concrete B) were prepared with sands havin... more AbstractTwo types of concrete mixtures (Concrete A and Concrete B) were prepared with sands having different fineness modulus. Sand was replaced with coal bottom ash (CBA) at 20, 30, 40, 50, 75, and 100% levels in both concrete mixtures. Laboratory tests were performed to study the effect of CBA on compressive strength, sorptivity, chloride permeability, drying shrinkage, and sulfate and acid resistance of concrete. At 7 days, for both grades of concretes, concrete mixtures incorporating CBA showed lower compressive strength. At 28 days, for Concrete A, no significant effect of CBA on compressive strength was observed. However, in case of Concrete B, concrete mixtures containing more than 50% CBA displayed lower 28-day compressive strength than that of control concrete. With age, compressive strength of bottom ash concrete mixtures increased at faster rate. Bottom ash concrete mixtures displayed higher sorptivity, lower chloride permeability, and drying shrinkage. For both grades of concretes, resistance ...
Latent heat thermal energy storage systems incorporate phase change materials (PCMs) as storage m... more Latent heat thermal energy storage systems incorporate phase change materials (PCMs) as storage materials. The high energy density of PCMs, their ability to store at nearly constant temperature, and the diversity of available materials make latent heat storage systems particularly competitive technologies for reducing energy consumption in buildings. This work reviews recent experimental and numerical studies on the integration of PCMs in building envelopes for passive energy storage. The results of the different studies show that the use of PCMs can reduce the peak temperature and smooth the thermal load. The integration of PCMs can be done on the entire building envelope (walls, roofs, windows). Despite many advances, some aspects remain to be studied, notably the long-term stability of buildings incorporating PCMs, the issues of moisture and mass transfer, and the consideration of the actual use of the building. Based on this review, we have identified possible contributions to i...
Latent heat thermal energy storage systems incorporate phase change materials (PCMs) as storage m... more Latent heat thermal energy storage systems incorporate phase change materials (PCMs) as storage materials. The high energy density of PCMs, their ability to store at nearly constant temperature, and the diversity of available materials make latent heat storage systems particularly competitive technologies for reducing energy consumption in buildings. This work reviews recent experimental and numerical studies on the integration of PCMs in building envelopes for passive energy storage. The results of the different studies show that the use of PCMs can reduce the peak temperature and smooth the thermal load. The integration of PCMs can be done on the entire building envelope (walls, roofs, windows). Despite many advances, some aspects remain to be studied, notably the long-term stability of buildings incorporating PCMs, the issues of moisture and mass transfer, and the consideration of the actual use of the building. Based on this review, we have identified possible contributions to i...
The aim of this work is to understand the influence of the microstructuralgeometric parameters of... more The aim of this work is to understand the influence of the microstructuralgeometric parameters of porous building materials on the mechanisms of coupled heat, air and moisture transfers, in order to predict behavior of the building to control and improve it in its durability. For this a multi-scale approach is implemented. It consists of mastering the dominant physical phenomena and their interactions on the microscopic scale. Followed by a dual-scale modelling, microscopic-macroscopic, of coupled heat, air and moisture transfers that takes into account the intrinsic properties and microstructural topology of the material using X-ray tomography combined with the correlation of 3D images were undertaken. In fact, the hygromorphicbehavior under hydric solicitations was considered. In this context, a model of coupled heat, air and moisture transfer in porous building materials was developed using the periodic homogenization technique. These informations were subsequently implemented in...
Numerical Heat Transfer, Part A: Applications, 2016
ABSTRACT The focus of this paper was to examine the contribution of two key mechanisms—moisture c... more ABSTRACT The focus of this paper was to examine the contribution of two key mechanisms—moisture convection and diffusion–on heated air and moisture transfer in porous building envelopes and to define the validity of the sub-models. A numerical simulation was performed and is focused on the one-dimensional problem for drying test boundary conditions. Thereafter, a detailed parametric analysis was carried out in order to investigate the influence of typical nondimensional parameters. Results show that convection is a prominent driving potential with respect to the diffusion process when the hygric state is stable between the environment and the envelope.
Advances in Multi-Physics and Multi-Scale Couplings in Geo-Environmental Mechanics
Abstract: Structures’ durability and their degradation mechanisms have received much interest fro... more Abstract: Structures’ durability and their degradation mechanisms have received much interest from the scientific community and project owners. Cementitious materials are the most common building materials. They have a complex microstructure with a highly heterogeneous and random character of their mechanical and physical properties. Various processes affect their properties: chemical, such as cement hydration, and physical, such as heat and moisture exchange. The latter, which relate to variations in the water content and its distribution in the material, have an important influence on the global behavior of cementitious materials. The process of convective drying is a commonly encountered solicitation in the Civil Engineering field. It can be either natural, such as drying of concrete structural elements, or forced, such as drying in a research laboratory during the sample preparation and characterization.
AbstractTwo types of concrete mixtures (Concrete A and Concrete B) were prepared with sands havin... more AbstractTwo types of concrete mixtures (Concrete A and Concrete B) were prepared with sands having different fineness modulus. Sand was replaced with coal bottom ash (CBA) at 20, 30, 40, 50, 75, and 100% levels in both concrete mixtures. Laboratory tests were performed to study the effect of CBA on compressive strength, sorptivity, chloride permeability, drying shrinkage, and sulfate and acid resistance of concrete. At 7 days, for both grades of concretes, concrete mixtures incorporating CBA showed lower compressive strength. At 28 days, for Concrete A, no significant effect of CBA on compressive strength was observed. However, in case of Concrete B, concrete mixtures containing more than 50% CBA displayed lower 28-day compressive strength than that of control concrete. With age, compressive strength of bottom ash concrete mixtures increased at faster rate. Bottom ash concrete mixtures displayed higher sorptivity, lower chloride permeability, and drying shrinkage. For both grades of concretes, resistance ...
Latent heat thermal energy storage systems incorporate phase change materials (PCMs) as storage m... more Latent heat thermal energy storage systems incorporate phase change materials (PCMs) as storage materials. The high energy density of PCMs, their ability to store at nearly constant temperature, and the diversity of available materials make latent heat storage systems particularly competitive technologies for reducing energy consumption in buildings. This work reviews recent experimental and numerical studies on the integration of PCMs in building envelopes for passive energy storage. The results of the different studies show that the use of PCMs can reduce the peak temperature and smooth the thermal load. The integration of PCMs can be done on the entire building envelope (walls, roofs, windows). Despite many advances, some aspects remain to be studied, notably the long-term stability of buildings incorporating PCMs, the issues of moisture and mass transfer, and the consideration of the actual use of the building. Based on this review, we have identified possible contributions to i...
Latent heat thermal energy storage systems incorporate phase change materials (PCMs) as storage m... more Latent heat thermal energy storage systems incorporate phase change materials (PCMs) as storage materials. The high energy density of PCMs, their ability to store at nearly constant temperature, and the diversity of available materials make latent heat storage systems particularly competitive technologies for reducing energy consumption in buildings. This work reviews recent experimental and numerical studies on the integration of PCMs in building envelopes for passive energy storage. The results of the different studies show that the use of PCMs can reduce the peak temperature and smooth the thermal load. The integration of PCMs can be done on the entire building envelope (walls, roofs, windows). Despite many advances, some aspects remain to be studied, notably the long-term stability of buildings incorporating PCMs, the issues of moisture and mass transfer, and the consideration of the actual use of the building. Based on this review, we have identified possible contributions to i...
The aim of this work is to understand the influence of the microstructuralgeometric parameters of... more The aim of this work is to understand the influence of the microstructuralgeometric parameters of porous building materials on the mechanisms of coupled heat, air and moisture transfers, in order to predict behavior of the building to control and improve it in its durability. For this a multi-scale approach is implemented. It consists of mastering the dominant physical phenomena and their interactions on the microscopic scale. Followed by a dual-scale modelling, microscopic-macroscopic, of coupled heat, air and moisture transfers that takes into account the intrinsic properties and microstructural topology of the material using X-ray tomography combined with the correlation of 3D images were undertaken. In fact, the hygromorphicbehavior under hydric solicitations was considered. In this context, a model of coupled heat, air and moisture transfer in porous building materials was developed using the periodic homogenization technique. These informations were subsequently implemented in...
Numerical Heat Transfer, Part A: Applications, 2016
ABSTRACT The focus of this paper was to examine the contribution of two key mechanisms—moisture c... more ABSTRACT The focus of this paper was to examine the contribution of two key mechanisms—moisture convection and diffusion–on heated air and moisture transfer in porous building envelopes and to define the validity of the sub-models. A numerical simulation was performed and is focused on the one-dimensional problem for drying test boundary conditions. Thereafter, a detailed parametric analysis was carried out in order to investigate the influence of typical nondimensional parameters. Results show that convection is a prominent driving potential with respect to the diffusion process when the hygric state is stable between the environment and the envelope.
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Papers by Rafik Belarbi