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Experimental Investigation of Palm Fiber Surface Treatment Effect on Thermal, Acoustical, and Mechanical Properties of a New Bio-Composite

This work presented an experimental investigation on the use of a bio-composite as an insulating material in building. During the past few years, many projects have tried to create new composites with a high insulating properties, essentially thermal, which plays an important role in buildings energy efficiency (Chikhi et al. in Energy Build 66:267–273, 2013).

Par |2020-07-18T22:06:14+00:00juillet 18th, 2020|Communications internationales avec actes|Commentaires fermés sur Experimental Investigation of Palm Fiber Surface Treatment Effect on Thermal, Acoustical, and Mechanical Properties of a New Bio-Composite

Measurement of pore size distribution of building materials by thermal method

The present work focuses on the study of the thermophysical properties of low porous insulation materials. In peculiar, we investigate the pore structure of composite materials and cements by thermal method. This method, adapted for fragile materials, is based on an existing model which allows the determination of pore size distribution. Firstly, the existing analytical model is presented. The thermal conductivity is modeled by assimilating the studied medium to N fluid phases and one solid phase in series / parallel. Secondly, some extensions to this model are proposed. In particular, we show that in the case of a single pore size, it is possible to obtain a finer pore size distribution by means of a normal law. We also show for the first time that the normalization of the thermal conductivity is an interesting way to study the pore size distribution of a material without knowing the overall porosity rate (which strongly depends on the method used). Furthermore, this model and its extensions have been successfully applied to different kinds of materials (plant fiber composites and cements). Fibers reinforced composites have one class of pores around 30 – 60 lm. Chemical treatments do not affect this pore size. Cements show a macroporosity (around 20 lm) which is often underestimated.

Par |2020-07-16T15:43:28+00:00juillet 16th, 2020|Articles dans revues internationales à comité de lecture|Commentaires fermés sur Measurement of pore size distribution of building materials by thermal method

Etude des performances thermiques de matériaux à matrice cimentaire renforcés par des fibres de bois de palmier traitées

Ce projet vise à déterminer la faisabilité technique de l’introduction de déchets de palmier à l’état brut et après traitement chimique dans du ciment afin d’élaborer un nouvel éco-composite de construction qui soit léger, bon isolant thermique et acoustique. Dans les composites, l’augmentation de la fraction massique de fibres induit une diminution progressive de la conductivité et la diffusivité thermique et s’accompagne d’une perte des propriétés mécaniques et d’une diminution de la densité. Le dégraissage des fibres améliore les propriétés mécaniques, les composites obtenus sont moins fragiles que ceux obtenus à partir de fibres brutes.

Par |2020-07-16T12:38:43+00:00juillet 16th, 2020|Communications nationales avec actes|Commentaires fermés sur Etude des performances thermiques de matériaux à matrice cimentaire renforcés par des fibres de bois de palmier traitées

Paraffin/ Expanded Perlite/Plaster as Thermal Energy Storage Composite

The use of thermal energy storage composite materials allows passive cooling and heating in buildings, yielding substantial energy savings. The purpose of this study is to develop and test a new phase change material (PCM) composite by loading expanded perlite (EP) with paraffin (RT27) to form plaster composites. The leakage tests allowed to unfold the optimal RT27 loading rate. To avoid paraffin leakage out of the composite structure, a waterproof product, Sikalatex® (SL), was used to coat the RT27/EP composite before mixing it with plaster. Thermal properties of RT27/EP/SL integrated in plaster were assessed. The effect of aluminum powder insertion on enhancing the composite thermal properties, was investigated. Paraffin loading rate was 60% by direct impregnation. FTIR analyses proved that the produced composites showed a good chemical compatibility between different components. DSC analyses revealed that composites have suitable energy storage capacities of 51.57 ± 0.01 and 49.95 ±0.15 kJ.kg-1 for RT27/EP/SL and RT/EP/SL/Al, respectively. These composites are suitable for indoor temperature regulation. Thermal cycling tests showed a good thermal stability of plaster PCM composite. Thermal conductivity of plaster composite containing 50% wt of RT27/EP/SL/Al composite was increased by 80% and 68% at 12°C and 40°C respectively compared with the aluminum free composite.

Par |2020-07-16T10:08:45+00:00juillet 16th, 2020|Articles dans revues internationales à comité de lecture|Commentaires fermés sur Paraffin/ Expanded Perlite/Plaster as Thermal Energy Storage Composite

Thermophysical characterization of Posidonia Oceanica marine fibers intended to be used as an insulation material in Mediterranean buildings

The present work focuses on the study of the thermophysical properties of Posidonia Oceanica natural fibers in order to investigate the potential of their use as loose-fill thermal insulation material in the Mediterranean construction. 24 samples were prepared. Bulk densities were varied from 17 kg m-3 to 155 kg m-3. Chemical alkali treatments with various conditions were applied to these fibers. The influence of treatments and of density on morphological and thermophysical properties of samples was evaluated. The surfaces were examined by using scanning electron microscopic. The thermal measurements were performed with the Hot Disk thermal constants analyzer. Results have shown that thermal conductivity decrease when density decreases until an optimum. After that, it increases as the density is reduced. Furthermore, regarding thermal conductivity, it was found out that the effect of chemical treatment is not significant mainly at the low densities. A very slight improvement was found at high densities with treated fibers, mainly the treatment that consists of immerging fibers twice in 2% sodium hydroxide solution during 2 h at 80 °C. Higher mass heat capacity was observed with this same treatment. Additionally, it was revealed in this study that Posidonia-Oceanica fibers have thermal conductivity and thermal diffusivity close to conventional insulation materials and higher mass heat capacity that reached 2533 J kg-1 K-1.

Par |2020-07-16T09:51:55+00:00juillet 16th, 2020|Articles dans revues internationales à comité de lecture|Commentaires fermés sur Thermophysical characterization of Posidonia Oceanica marine fibers intended to be used as an insulation material in Mediterranean buildings

Appreciation of the delay in the benefits of the thermal energy released by PCM in civil engineering structures

To optimize de-icers use in winter on roads and airports, some sustainable solutions were promoted in a global project entitled "Roads of the Future". PCM into pavements were then considered to rely on the released enthalpy to delay the occurrence of black ice or snow accumulation. Coupling a spectroscopic monitoring of the PCM behavior and thermography on pavement surface indicated a significant delay between the phase change and the thermal manifestation of the released energy. Considering an accurate description of PCM according to cooling weather phenomena, these elements might provide valuable information for numerical models.

Par |2020-06-29T11:41:04+00:00juillet 9th, 2019|Communications internationales avec actes, Productions|Commentaires fermés sur Appreciation of the delay in the benefits of the thermal energy released by PCM in civil engineering structures

Investigation of Fiber Surface Treatment Effect on Thermal, Mechanical and
Acoustical Properties of Date Palm Fiber-Reinforced Cementitious Composites

Abstract High energy consumption in the building sector appeals for the implementation and the improvement of innovative approaches with low-environmental impact. The development of eco-friendly composites as insulating materials in buildings provides practical solutions for reducing energy consumption. Different mass proportions (2.5%, 10%, and 20%) of untreated and chemically treated palm fibers were mixed with (cement, water and sand) so as to prepare novel composites. Composites were characterized by measuring water absorption, thermal conductivity, compressive strength and acoustic transmission. The results reveal that the incorporation of untreated and chemically treated date palm fibers reduces novel composites’ thermal conductivity and the mechanical resistance. Thermal measurements have proved that the loading of fibers in composites decreases the thermal conductivity from 1.38 W m−1 K−1 for the reference material to 0.31 W m−1 K−1 for composites with 5% of treated and untreated fibers. The acoustical insulation capacity of untreated palm fiber-reinforced composites (DPF) was the highest at 20% fiber content, whereas treated palm fiber-reinforced composites (TPF) had the highest sound insulation coefficient for fiber content lower than 10%. Compressive strength, thermal conductivity and density correlation showed that only chemically treated fiber-reinforced composites (TPF) are good candidates for thermal and acoustic building insulations.

Par |2020-07-18T21:23:05+00:00juillet 9th, 2019|Articles dans revues internationales à comité de lecture, Productions|Commentaires fermés sur Investigation of Fiber Surface Treatment Effect on Thermal, Mechanical and
Acoustical Properties of Date Palm Fiber-Reinforced Cementitious Composites

Benchmark de méthodes d’identification de paramètres sur données simulées : application à la mesure sur site de la résistance thermique de parois de bâtiments en utilisant la thermographie infrarouge active

Résumé – Ce travail porte sur la réalisation d’un benchmark de méthodes d’identification en vue de mesurer sur site la résistance thermique de parois de bâtiment par thermographie infrarouge active. Les mesures virtuelles sont générées à l’aide de différents Modèles Physiques Générateurs. Plusieurs méthodes d’estimation de paramètres sont comparées. Les résultats présentés se focalisent sur les parois ITI (Isolation Thermique par l’Intérieur) et montrent qu’une estimation satisfaisante de la résistance thermique de la paroi est possible dans de nombreux cas.