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International audience; Direct bonding is a well-known process. However in order to use this process in spatial instrument fabrication the mechanical resistance needs to be quantified. In order to improve bonded strength, optimal parameters of the process are found by studying theinfluence of annealing time, temperature and roughness which are studied using three experimental methods: double shear, cleavage and wedge tests. Those parameters are chosen thanks to the appearance of time/temperature equivalence. Results brought out a predictive model of the bonding energy.

International audience; In building construction, because of the hygroscopic nature of wood and earth brick and the low adhesion between these materials, cracks are formed at their interface when they are assembled. Geopolymer binder has been show to create strong bonds between wood and earth brick. Assemblies of wood and extruded earth brick with geopolymer binder were manufacture and tested. Double shear tests at two scales were carried out that provided evidence of good adhesion and information about the influence of the type of brick on shear behavior. The workability of the binder was improved by adding siliceous aggregates. The mortar obtained has an improved compressive strength, ranging from 3 to 8 MPa, depending on the aggregate size. FTIR measurements and thermal analysis were performed to determine the reaction mechanism

Bu tez çalışmasında; imalat sektöründe, otomotiv sektöründe, çeşitli mühendislik alanlarında ve günlük hayatta bir çok yerde karşılaştığımız çeşitli sebeplerden dolayı oluşan darbe kuvvetlerinin bertaraf edilmesinde kullanılmak üzere iki farklı takviye malzemesinden üretilmiş iki tür kompozit darbe emicisi üzerinde araştırmalar yapılmıştır. Üzerinde çalışılan kompozit karışımlar; ilk olarak çelik talaşı ile belirli oranlarda karışım yapılmış vinil ester reçine ve ikinci olarak granül haldeki atık kauçuk ile belirli oranlarda karışım yapılmış vinil ester reçinedir. Üzerinde çalışılan malzemeler sabit presleme basıncında ve 3 farklı karışım oranında elde edilmiştir. Üretimde numune boyutlarını standart hale getirebilmek için değişken kütle - sabit hacim kuralı esas alınmıştır. Üretilen numunelere düşük hızlı darbe, basma ve çift kesme deneyleri uygulanmış ve kuvvet - zaman, kuvvet - yer değiştirme grafikleri elde edilmiştir. Bu grafiklere bağlı olarak toplam enerjiyi yutma ve yansıtma oranlarındaki değişimler yorumlanmıştır., In this thesis, investigations were carried out on two types of composite for shock absorbing ability, which were produced two different reinforcement material . Disposal of impact forces generated from manufacturing sector, automotive industry, where we encountered various engineering fields and in a daily life due to various reasons. Composite mixtures studied, firstly the mixture of steel chip with vinyl ester resin were mixed in a specific proportions, secondly in certain amounts of mixture were made from a granulated waste rubber and vinyl ester resin were used. The studied material was obtained at constant pressure by pressing and three different mixing ratio. Variable mass – Constant volume rule is used to standardization the size of the sample. Low-velocity impact, compression and double shear tests were applied to the samples and the force-time, force-displacement graphs were obtained. This chart depending on the changes the total energy absorption and reflection of the samples were interpreted with respect to these graphics.

International audience; This paper focuses on investigating the bonding fatigue performance between two asphalt concrete (AC) layers. For purposes of this experimental campaign, a customised double shear testing device was designed. Two interface conditions have been analysed herein: with and without a tack coat. Moreover, the corresponding fatigue behaviour has been analysed at two temperatures: 10 °C and 20 °C. As expected, the absence of a tack coat leads to a decrease in bonding fatigue performance. Since fatigue tests are highly time-consuming, a method that allows predicting the conventional interface fatigue law from accelerated shear fatigue tests has been proposed. Other novel findings on interface fatigue behaviourwill also be discussed. In addition to these fatigue results, an interface failure model is proposed to evaluate the interface lifetime. Incorporating interface fatigue performance into pavement analysis proves to be a key parameter in describing in situ pavement conditions and assessing pavement durability.

The research work presented in this PhD thesis lies within the framework of a partnership between the laboratory Mechanics and Modeling of Materials and Structures in Civil Engineering (3MSCE, University of Limoges) and Eurovia, a subsidiary of the VINCI Group. The study aims at better understanding the mechanistic behavior of tack coats spread at the interface between two asphalt concrete (AC) layers. This behavior is characterized through a large experimental campaign. Then, the tests results are used in a finite element program. This program allows the pavement structure engineer to predict, on the one hand, the durability of the bonding at the interface, and on the other hand, the effect of modeling the interface behavior on the pavement response. In this research project, a laboratory double shear test device is designed and manufactured. By means of a mono-axis hydraulic press, the device allows applying a double shear loading at the interfaces of a symmetrical specimen which is consisted of three AC layers. Thus, monotonic, oligocyclic and fatigue tests are carried out at 10 and 20°C on an interface BBTM/BBSG (very thin AC layer overlaid on a dense AC layer). This interface is with or without tack coat (a cationic rapid-set emulsion with pure bitumen). The oligocyclic and fatigue tests were carried out in a force controlled mode, and lead to very innovative and interesting results. Three failure criteria are analyzed. The results clearly show that the lack of tack coat reduces the fatigue performance of the bonding (interface). Through the analysis of the results, a method is proposed, and allows predicting the fatigue law of the bonding from the monotonic shear tests results. This shear tests campaign is completed by a series of laboratory monotonic torque tests. Besides the characterization of the tack coats shear behavior, the experimental conditions where the torque and the double shear tests results are similar are specified. The last part of this work deals with, on the one hand, the effect of the interface shear behavior on the pavement structure design, and on the other hand, the effect of the repeated horizontal loads on the fatigue of the bonding at the interface. Two finite element models (2D and 3D) are developed in order to evaluate the mechanistic response of the pavement subjected to the French standard axle. Findings from this numerical simulation show that, when taking into account the horizontal loads, the fatigue of the bonding becomes predominant during the pavement structure design., Cette thèse s'inscrit dans le cadre d'une collaboration entre le laboratoire Mécanique et Modélisation des Matériaux et Structures du Génie Civil (3MsGC) de l'Université de Limoges, et Eurovia, une société du groupe VINCI. Les travaux réalisés dans cette thèse visent à une meilleure connaissance du comportement mécanique des couches d'accrochages mises en oeuvre à l'interface de deux couches d'enrobés bitumineux. Afin de caractériser ce comportement, un large travail expérimental a été réalisé. Les résultats de cette campagne d'essais ont permis d'alimenter le modèle éléments finis développé dans le but de prédire la durabilité du collage à l'interface des couches de chaussée. Ce modèle permet également d'étudier l'effet de la modélisation ou non du comportement de l'interface sur le dimensionnement de la chaussée. Afin de mener à bien la campagne expérimentale de ce travail, un prototype de dispositif d'essai a été conçu et réalisé. Au moyen d'une presse servohydraulique mono-axe, le dispositif permet d'appliquer une sollicitation de double cisaillement aux interfaces d'une éprouvette symétrique constituée de trois couches d'enrobés bitumineux. Ainsi, des essais monotones, oligocycliques et de fatigue ont été réalisés à 10 et à 20°C sur une interface BBTM/BBSG, comportant ou non une couche d'accrochage à base de bitume pur. Les essais oligocycliques et de fatigue, réalisés en mode de contrôle de force, ont permis d'obtenir des résultats très satisfaisants, et très peu dispersés. Trois critères de rupture d'interface ont été analysés. Les résultats obtenus montrent que l'absence de couche d'accrochage réduit considérablement la performance à la fatigue du collage à l'interface. Les résultats d'essais ont également permis de proposer une méthode qui permet de prédire la loi de fatigue du collage à partir des résultats d'essais monotones de cisaillement. Cette campagne d'essais de cisaillement est complétée par une série d'essais monotones de torsion. Outre la caractérisation du comportement mécanique des couches d'accrochage, les résultats ont permis de déterminer les conditions expérimentales dans lesquelles les essais en laboratoire de cisaillement et de torsion sont corrélables. L'essai monotone de torsion présente l'avantage d'être réalisable sur chantier. Une dernière partie de ce travail est consacrée à l'analyse de l'influence, d'une part, du comportement mécanique du collage à l'interface lors du dimensionnement de la structure de chaussée, et d'autre part, des sollicitations tangentielles répétées sur la tenue à la fatigue du collage à l'interface. Deux modèles éléments finis (2D et 3D) sont développés pour étudier la réponse mécanique de la structure sollicitée par l'essieu standard français. Les résultats obtenus montrent que sur certaines sections de chaussée, la prise en compte des sollicitations tangentielles conduit à considérer la fatigue des interfaces comme prédominante lors du dimensionnement.

International audience; Direct bonding is a well-known process. However in order to use this process in spatial instrument fabrication the mechanical resistance needs to be quantified. In order to improve bonded strength, optimal parameters of the process are found by studying the influence of annealing time, temperature and roughness which are studied using three experimental methods: double shear, cleavage and wedge tests. Those parameters are chosen thanks to the appearance of time/temperature equivalence. Results brought out a predictive model of the bonding energy.