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The bender element (BE) test has been widely used for the dynamic characterization of soil specimens at low-shear strain levels. However, the actual behavior of the BE inside a soil specimen remains unknown. Thus, the current ASTM standard does not consider the interference of compressional and shear waves in BE testing, which can lead to significant errors in the evaluation of shear wave velocities. The main objective of this paper is to present a numerical model of the BE system to better understand the response of the BEs inside a soil sample. The model is calibrated, verified, and then used to demonstrate the importance of taking into consideration the interaction between compressional and shear waves for the correct interpretation of BE measurements. The model successfully captured the measured vibrations of the BE in air as well as inside transparent soils. More importantly, the numerical simulations provide a new understating of the significant interactions of P waves and S waves especially in clay soils. Thus, the proposed coupled piezoelectric and solid mechanics model can be used to study the soil-BE interaction so that sound recommendations can be given to improve the interpretation of BE tests in different soils. Key words: bender element test, laser vibrometer, wave propagation, solid mechanics, piezoelectric, finite element method. L'essai par elements piezoceramiques (<>, BE) a ete largement utilise pour la caracterisation dynamique des echantillons de sol a des niveaux de deformation de cisaillement faibles. Cependant, le comportement reel du BE a l'interieur d'une eprouvette de sol reste inconnu. Ainsi, la norme ASTM actuelle ne tient pas compte de l'interference des ondes de compression et de cisaillement dans les essais BE, ce qui peut entrainer des erreurs importantes dans revaluation des vitesses des ondes de cisaillement. L'objectif principal de cet article est de presenter un modele numerique du systeme BE pour mieux comprendre la reponse des BE a l'interieur d'un echantillon de sol. Le modele est calibre, verifie, puis utilise pour demontrer l'importance de prendre en compte l'interaction entre les ondes de compression et de cisaillement pour une interpretation correcte des mesures BE. Le modele a reussi a capturer les vibrations mesurees du BE dans l'air ainsi qu'a l'interieur de sols transparents. Plus important encore, les simulations numeriques permettent de mieux comprendre les interactions significatives entre les ondes P et les ondes S, en particulier dans les sols argileux. Ainsi, le modele couple piezoelectrique et de mecanique solide propose peut etre utilise pour etudier l'interaction sol-BE de sorte que des recommandations judicieuses puissent etre donnees pour ameliorer l'interpretation des essais BE dans differents sols. [Traduit par la Redaction] Mots-cles : essai de l'element piezoceramique, vibrometre laser, propagation des ondes, mecanique des solides, piezoelectrique, methode des elements finis., 1. Introduction The dynamic soil properties play an important role in the design of earthquake-resistant structures and foundations. The bender element (BE) test and resonant column (RC) test are the [...]

Warm mix asphalt (WMA) technology has the capability of lowering asphalt mixing and compacting temperature by 30[degrees]C or more without compromising the performance of asphalt pavement. This results to a lower cooling rate that allows for long haul, and sufficient compaction time. The objective of this study is to evaluate the effectiveness of the common chemical additives on the properties of WMA mixtures through field and laboratory testing programs. Three dosages (0.3, 0.5, and 0.7% by weight of asphalt cement) were used without changing the job mix formula. Among the different additive dosage used, 0.5% had a better overall performance. For example, the moisture sensitivity test for the 0.5% WMA indicated the highest tensile strength ratio; subsequently, low moisture damage. All WMA mixtures had low rutting resistance potential and higher cracking resistance compared to conventional mix. Key words: warm mix asphalt (WMA), chemical additive, moisture susceptibility, dynamic modulus, Hamburg wheel-tracking, cracking resistance. La technologie du melange d'asphalte tiede (MAT) permet de reduire la temperature de melange et de compactage de l'asphalte de 30[degrees]C ou plus sans compromettre la tenue de la chaussee d'asphalte. Il en resulte une vitesse de refroidissement plus faible qui permet un temps de prise plus long et un temps de compactage suffisant. L'objectif de cette etude est d'evaluer l'efficacite des additifs chimiques courants sur les proprietes des melanges MAT au moyen de programmes d'essais sur le terrain et en laboratoire. Trois doses (0,3, 0,5 et 0,7% en poids de ciment asphaltique) ont ete utilisees sans changer la composition de l'enrobe de travail. Parmi les differentes doses d'additif utilisees, 0,5% avait un meilleur rendement global. Par exemple, l'essai de sensibilite a l'humidite pour le MAT de 0,5% indiquait le rapport de resistance a la traction le plus eleve; par la suite, les dommages causes par l'humidite etaient faibles. Tous les melanges MAT presentaient une faible resistance a l'ornierage et une resistance a la fissuration plus elevee que le melange conventionnel. [Traduit par la Redaction] Mots-cles : melange d'asphalte tiede (MAT), additif chimique, sensibilite a l'humidite, module dynamique, bande de roulement (<< Hamburg wheel-tracking >>), resistance a la fissuration., Introduction In recent years, there have been significant efforts in reducing the use of non-renewable energy sources (e.g., fossil fuels: coal and petroleum), conserving energy, and reducing emissions due to [...]

Objectives: To evaluate the esthetic outcome, as well as clinical, radiographic, and volumetric tissue alterations 1 year after immediate implant placement (IIP) with connective tissue grafting (CTG) versus dual‐zone concept (DZ) at sites with thin labial bone in the esthetic zone. Materials and Methods: This randomized clinical trial included 30 patients treated with IIP simultaneous with either CTG or DZ (n = 15 each). Pink esthetic score (PES) was assessed 6 months after crown placement as the primary outcome. Amount of bone labial to the implant, labio‐palatal ridge reduction, and crestal bone changes were measured via CBCT after 1 year. Volumetric analysis of linear labial soft tissue contour, interdental, and mid‐facial soft tissue level changes, and total volume loss (mm3) were measured after 1 year. Results: Similar PES was observed in the CTG (12.53 ± 1.13) and DZ (12.13 ± 1.55) groups, with no significant difference (p = 0.42). Likewise, there were no statistically significant differences found between the two groups in labio‐palatal bone reduction (mm&%), interdental papillae, and mid‐facial gingival levels (p > 0.05). However, the mean vertical crestal bone changes in the CTG and DZ groups were −1.1 ± 0.6 mm and 0.2 ± 1.0 mm, respectively, with a statistically significant difference (p = 0.0002). Moreover, CTG revealed less linear and total volume (mm3) loss in the labial soft tissue which was statistically significant compared to DZ (p = 0.007). Conclusion: Both groups demonstrated the same PES, nevertheless, volumetric analysis revealed twice total labial volume loss in DZ compared to CTG. It might be concluded that the use of CTG with IIP caused less horizontal reduction in the supra‐implant complex compared to the DZ. [ABSTRACT FROM AUTHOR]