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International audience; In this work we focus on the study of the acoustic and mechanical behavior of compressed earth blocks (CEBs). The aim was to study the influence of compaction pressure on the compressive strength and intrinsic acoustic parameters influencing sound absorption of these materials (porosity, tortuosity, airflow resistivity, viscous characteristic length). Specimens made by varying the applied compaction pressure and therefore having various bulk densities were studied. Low bulk density CEBs where stabilized by adding 15% cement. The acoustic absorption coefficients of the different specimens were determined experimentally employing data obtained using the Kundt tube. The intrinsic acoustic parameters were identified by minimizing the discrepancies between the experimentally measured absorption coefficient (α) and the theoretical one modeling the CEBs using the equivalent fluid model. The results showed that the acoustic and mechanical behavior of CEBs were strongly influenced by the applied compaction pressure including, inter alia, the bulk density of the specimen and the added cement used as stabilizer.

Compressed earth blocks (CEB) were used for the construction, always and until now systematically with a bulk density of about 1800 and 2100 kg m −3 . These earth construction materials have a relatively high thermal conductivity of about 1.1 W m −1 K −1 . This study aims to obtain lightweight CEB by varying their bulk density in order to modify their porosity and consequently to act on their thermal conductivity. The approach adopted here involves an experimental study of the influence of compaction pressure on the bulk density of the compressed earth block (CEB) and its effects on their thermal performance (thermal conductivity and thermal effusivity) and mechanical properties (compressive strength and modulus of elasticity). Results show that bulk density has a strong influence on thermal and mechanical behavior of CEB. The decrease in the bulk density of CEB was accompanied by a significant reduction in their thermal conductivity and their thermal effusivity. This variation in thermal properties as a function of bulk density is performed linearly. However, the bulk density should not decrease under certain minimum values below which the CEB lose their cohesion and compressive strength.

This study describes the development of an experimental setup that tracks the evolution of the melting and freezing fronts of a Phase Change Material (PCM), in this case paraffin. The results obtained enable the examination of the shape and movement of the melting front of the PCM. Two modes of heat transfer were identified during the melting process: conduction when melting began and natural convection, which becomes dominant in the remainder of the cycle. Monitoring of the melt over time shows that the melt fraction, expressed as the ratio of the molten volume and solid volume, is proportional to the difference between the imposed temperature and the melting temperature. Experimental results confirm the linearity proposed by other researchers.

International audience; The objective of this work was to analyze the influence of compaction pressure on the intrinsic acoustic parameters (porosity, tortuosity, airflow resistivity, viscous and thermal characteristic lengths) of compressed earth blocks through their identification by solving an inverse acoustic wave transmission problem. A low frequency acoustic pipe (60-6000 Hz of length 22 m, internal diameter 3.4 cm) was used for the experimental characterization of the samples. The parameters were identified by the minimization of the difference between the transmission coefficients data obtained in the pipe with that from an analytical interaction model in which the compressed earth blocks were considered as having rigid frames. The viscous and thermal effects in the pores were accounted for by employing the Johnson-Champoux-Allard-Lafarge model. The results obtained by inversion for high-density compressed earth blocks showed some discordance between the model and experiment especially for the high frequency limit of the acoustic characteristics studied. This was as a consequence of applying high compaction pressure rendering them very highly resistive therefore degrading the signal to noise ratios of the transmitted waves. The results showed that the airflow resistivity was very sensitive to the degree of the applied compaction pressure used to form the blocks.

One of the challenges to reduce energy consumption in the construction sector around the world is the development of appropriate construction materials. Due to its thermal properties, gypsum plaster is one of these materials. Tunisia ranks second worldwide for the production of gypsum. It used almost exclusively for decorative purposes although it has interesting thermal properties. This study deals with the thermal characterization of Tunisian gypsum plaster from Meknassi region. Particular attention is paid to the effect of temperature and water content on the thermal conductivity. The plaster thermal conductivity vs. temperature exhibits an interesting behavior for buildings walls. Thermal analysis by DSC was conducted to explain this behavior.