title: Characterization of compressed earth blocks using low frequency guided acoustic waves.
abstract: The objective of this work was to analyze the influence of compaction pressure on the intrinsic acoustic parameters (porosity, tortuosity, air-flow 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 transmissions 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.
authors.affiliation: Laboratoire d'Énergétique et des Transferts Thermique et Massique, Faculté des Sciences de Bizerte, Université de Carthage, Carthage, Tunisia.
authors.forename: Mohamed
authors.initials: M
authors.lastname: Ben Mansour
authors.affiliation: Laboratoire de Mécanique et d'Acoustique, Centrale Marseille, Aix-Marseille University, 4 impasse Nikola Tesla, CS 40006, 13453 Marseille Cedex 13, France.
authors.forename: Erick
authors.initials: E
authors.lastname: Ogam
authors.affiliation: Laboratoire de Mécanique et d'Acoustique, Centrale Marseille, Aix-Marseille University, 4 impasse Nikola Tesla, CS 40006, 13453 Marseille Cedex 13, France.
authors.forename: Z E A
authors.initials: ZE
authors.lastname: Fellah
authors.affiliation: Laboratoire d'Énergétique et des Transferts Thermique et Massique, Faculté des Sciences de Tunis, Université de Tunis El Manar, Tunis, Tunisia.
authors.forename: Amel
authors.initials: A
authors.lastname: Soukaina Cherif
authors.affiliation: Laboratoire de Génie Civil, Ecole Nationale d'Ingénieurs de Tunis, Université de Tunis El Manar, Tunis, Tunisia.
authors.forename: Ahmed
authors.initials: A
authors.lastname: Jelidi
authors.affiliation: Laboratoire d'Energétique et des Transferts Thermique et Massique, Faculté des Sciences de Bizerte, Université de Carthage, Carthage, Tunisia.
authors.forename: Sadok
authors.initials: S
authors.lastname: Ben Jabrallah