Jacqueline Saliba

Institut de Mécanique et d'Ingénierie de Bordeaux | I2M Bordeaux · GCE

En vue de la transition écologique, construire en terre semble une option intéressante d'un point de vue environnemental. Les blocs de terre comprimée (BTC) sont faciles à mettre en oeuvre et assurent un confort hygrothermique. Néanmoins, les propriétés de la terre sont assez variables et il n'y a pas de formulation unique pour tous les types de te...

RESUME Le changement climatique et les périodes de sécheresse/humidification prolongées sont à l'origine d'importants dommages au niveau des infrastructures routières construites sur des sols argileux. En effet, les sols argileux présentent une variation de volume plus ou moins importante en fonction de leur teneur en eau et de leur minéralogie. Le...

Reinforced Concrete (RC) structures behaviour depends strongly on the variability of materials properties. This variability can be considered at different scales as concrete is a heterogeneous material constituted of several phases including different shapes, sizes and types of aggregates. In addition, at the structural level, the properties of con...

On the eve of changing laws concerning dredging practices, the recovery of sediments is necessary to create a viable economy for their management. With the evolution of the global environmental context which invites companies to reduce their impact by reusing local materials, dredged sediments represent a potential source of material. Thus, the obj...

Crack imaging in highly heterogeneous materials, such as concrete, plays a great role in structural health monitoring and non-destructive evaluation and testing. Numerous works have shown that Nonlinear Coda Wave Interferometry is a robust tool to assess the overall level of nonlinearity caused by micro or macrocracks in heterogeneous media. This w...

Machine learning has become a key branch in artificial intelligence by providing unique predictive modeling solutions. Predicting the compressive strength of concrete determined using non-destructive test techniques (NDT) includes high levels of uncertainty. This uncertainty directly depends on the repeatability of the measurement and the variabili...

L'objectif de ce travail est d'utiliser les sédiments de dragage vaseux du Grand Port Maritime de Bordeaux (GPMB) en tant que précurseur à la géopolymérisation pour développer un liant écologique tout en prenant en compte la variabilité de la fraction sableuse des sédiments en fonction du lieu de dragage. Afin d'étudier l'influence de la co-valoris...

Earth-based materials are currently receiving high attention, as they are considered as sustainable. In addition, the reuse of waste materials and more particularly recycled aggregates can boost circular economy while reducing landfilling and mineral resource depletion. Incorporating recycled aggregates in earth concrete can be an innovative way to...

RESUME : Le but de cette étude est l'optimisation de la résistance mécanique d'un liant géopolymère à base de sédiment de dragage à l'aide d'une analyse par plan de mélange. Différents paramètres de formulation sont étudiés : le rapport massique Na2SiO3/NaOH et le rapport massique Activateur/Précurseur. L'effet de ces paramètres sur la résistance à...

L’étude du comportement du béton sous l’effet de la température est primordiale afin d’évaluer le niveau de sécurité des structures sous sollicitations thermiques (cas des structures nucléaires par exemple). En effet, le chargement thermique conduit à plusieurs mécanismes d’endommagement responsables de la fissuration du béton. Une investigation ex...

Pourable earth concrete is a new form of earth construction that may be, for different applications, an alternative to cement concrete. The ecological benefits of such mixture will be more important if it was formed with fine recycled aggregate. However, earth construction materials are of low strength and thus the assessment of their mechanical pr...

Earth concrete, constituted mainly of raw earth, is a promising ecofriendly material for future constructions. However, it is composed of fine particles like clay which make it very sensitive to drying. The volume change induced by desiccation shrinkage can be responsible of cracking which can have a detrimental effect on the durability and mechani...

The evaluation of the spatial variability of concrete properties is an important issue for a better diagnosis of reinforced concrete structures. The combination between destructive techniques and nondestructive techniques (NDT) is a common practice to establish relationships between concrete properties and NDT measurements. Concrete properties can...

RESUME La variabilité spatiale des propriétés mécaniques est une information importante à prendre en compte pour fiabiliser l'évaluation du comportement mécanique des structures en béton. Cette variabilité peut être déterminée par exemple à partir de la variabilité spatiale des observables CND lors du diagnostic des ouvrages en béton armé. L'object...

The ecological material in this study comprises earth concrete made with recycled sand (RS). Three mixtures contain 20%, 30% and 40% of clay in addition to RS and one mixture of 30% of clay and natural sand (NS) were prepared. The specimens were exposed for 28 days to a relative humidity of RH=90% and RH=50%. Uniaxial compression cyclic tests were...

This work aims to assess the effect of different curing conditions on the fracture behavior of earth concrete mixtures made with natural sand (NS), recycled sand (RS) and different percentage of clay at the age of 14, 28 and 90 days. Compressive tests were monitored in parallel with the acoustic emission (AE) and the digital image correlation (DIC)...

This paper deals with the detection and monitoring of damage of a three-dimensional carbon/carbon composite (3D C/C) under tensile loading. In fact, due to the manufacturing process, the existing cracking network of 3D C/C at the initial state may be quite extended which may affect the mechanical behavior and in some cases lead to the premature rup...

The mechanical behavior of earth concrete for sustainable construction has been studied in this paper. The effect of flax fibers on the fracture behavior has been monitored using digital image correlation (DIC) and acoustic emission (AE) techniques to better understand the fracture process and damage mechanism. Three-point bending tests have been c...

Earth concrete or concrete based on soil materials presents a high percentage of fine particles (clay) which makes it susceptible to plastic shrinkage cracking in its fresh state that affects its durability. In this study, natural flax fibers with different mass percentages (0%, 0.3% and 0.6%) and lengths (12 mm, 24 mm, 50 mm) have been added to ea...

This study aims to optimize the composition of new ecological concrete constituted of upgraded excavated soil. The novelty of this study is the fact that earth concrete is poured with classical vibration as ordinary concrete. Several soil concrete mixtures, composed of different proportions of clayey soil, sandy soil and small amounts of cement, li...

One of the main interests of the Acoustic Emission (AE) technique is its capability to detect and localise damage in structures. In this paper, the accuracy of AE sources localisation in concrete is studied. Several methods related to the choice of the onset detection of AE signals and to the location algorithm are evaluated and compared. The resul...

Cracking in reinforced concrete structures is of major concern since it may affect their durability and structural integrity. Cracking is mainly influenced by stress distribution along the interface between steel and concrete which is responsible of transferring load from steel bar to the surrounding matrix. Thus, quantitative evaluation of steel-c...

Cracking in Reinforced Concrete (RC) structures may impact their durability and their structural integrity. Cracking is mainly influenced by stress distribution along the interface between steel and concrete. Thus, quantitative evaluation of steel-concrete bond, which is responsible of transferring load from steel bar to the surrounding matrix, and...

The diagnosis of reinforced concrete is essential to detect the degradation and thus maintain the structural performance of civil engineering structures. This paper aims to establish a mathematical relationship between the ultrasonic pulse velocity UPV (considered as an observable variable) and two concrete properties indicators (compressive streng...

The aim of this paper is to study the reinforced concrete short tie-rods behavior using the adhesion-slip curve shape between steel and concrete adopted by the European Concrete Committee. We are interested here in short tie-rods without main cracks for which we calculate and measure the maximum mobilization state of steel-concrete adhesion, and be...

In civil engineering, the control of creep has a major role in concrete structure design. Indeed, the viscoelasticity of concrete leads to delayed deformations which could be at the origin of cracking in structures. So, these delayed strains have an impact on their safety margin and life time, especially when they are subjected to high loads. For e...

L’objectif de ce travail est de valoriser des sédiments non traités dans la formulation d’un béton allégé. Pour cela, un béton mousse innovant a été développé en remplaçant le sable fin par des sédiments. Plusieurs essais expérimentaux ont été réalisés pour, dans un premier temps, caractériser les sédiments et dans un second temps déterminer les pr...

Two functions are regularly tested on containment walls in order to anticipate a possible accident. The first is mechanical to resist a possible internal over-pressure and the second is to prevent leakage. The AAPR reference accident is the rupture of a pipe in the primary circuit of a nuclear plant. In this case, the pressure and temperature can r...

Under mechanical loading, brittle matrix composites develop various damage processes which include cracking of matrix and fiber/matrix interface. Cohesive zone models (CZM) are widely used to model interfacial damage. The aim of this paper is to propose an alternative approach based on a damage model associated to a diffuse meshing method. In this...

The monitoring of concrete structures by the acoustic emission (AE) technique allows the detection and the localization of damage. The source location is determined by a triangulation algorithm based on the arrival time of AE signals recorded by sensors placed at the surface of the material, and the measured concrete wave velocity. The accuracy of...

In this paper, the fracture process zone (FPZ) is investigated on unnotched and notched beams with different notch depths. Three-point bending tests have been realized on plain concrete under crack mouth opening displacement (CMOD) control. Crack growth is monitored by applying the acoustic emission (AE) technique. The comparison with a numerical m...

The fracture process zone (FPZ) was investigated on unnotched and notched beams with different notch depths. Three point bending tests were realized on plain concrete under crack mouth opening displacement (CMOD) control. Crack growth was monitored by applying the acoustic emission (AE) technique. In order to improve our understanding of the FPZ, t...

The fracture process zone (FPZ) was investigated on unnotched and notched beams with different notch depths. Three point bending tests were realized on plain concrete under crack mouth opening displacement (CMOD) control. Crack growth was monitored by applying the acoustic emission (AE) technique. In order to improve our understanding of the FPZ, t...

Fracture of quasibrittle materials as cementitious materials is characterized by the development of a micro-cracked damaged zone ahead of the main crack, called Fracture Process Zone (FPZ). This zone is responsible for the dissipation the elastic energy stored in the structure due to stress redistribution. The characterization of the FPZ constitute...

Le bois est un matériau naturel de plus en plus utilisé dans la construction. Afin d'améliorer les outils de conception des structures en bois, la connaissance des mécanismes de fissuration est un élément primordial à appréhender. L'objectif de ce travail s'oriente vers l'étude des propriétés mécaniques et des mécanismes d'endommagement du bois mas...

Le suivi d'endommagement du béton par émission acoustique (EA) est parmi les seules techniques qui permettent de détecter et de localiser les micros-endommagements qui surviennent lorsque les capacités de résistance locales du matériau sont dépassées. Cette localisation s'effectue à partir de l'analyse des temps de vol des ondes élastiques reçues p...

RÉSUMÉ. Les bétons présentent une rupture quasifragile du fait de la présence d'une zone d'élaboration de la fissure (FPZ), principalement microfissurée, se développant en avant du front de fissure. La puissance de calcul actuelle a permis le développement de modèles mésoscopiques ayant pour objectif de représenter la participation de la géométrie...

Despite the large number of studies, the mechanisms involved during creep of concrete are still not well known and particularly tensile creep which is a major issue especially in the case of special concrete structures. The objective of this study is to suggest an assessment of the damage mechanisms occurring during the different phases of creep. T...

The purpose of this paper is to analyse the development and the evolution of the fracture process zone during fracture and damage in quasi-brittle materials. A model taking into account the material details at the mesoscale is used to describe the failure process at the scale of the heterogeneities. This model is used to compute histograms of the r...

In order to design reliable, large concrete structures, prediction of long-term behavior of concrete by considering a coupling between creep and damage is important. The acoustic emission (AE) technique can be used to perform the characterization of the influence of creep on crack development. In addition, an unsupervised pattern recognition analys...

The service-life of concrete structures depends on the delayed strains that appear due to creep phenomenon. Few are the studies that treated the effect of the dimensions of concrete specimens on the amplitude and the kinetics of creep and the results show many contradictions. Thus, to design reliable civil engineering structures, the knowledge of t...

In order to build sustainable structures, the study of mechanical behavior must integrate with local phenomena, e.g. fracture propagation and localization zone. Fracture in concrete usually develops in the form of localized zone of microcracks which then coalesce into macrocrack of significant crack openings. In this paper, fracture process in geom...

Concrete is a heterogeneous material that develops delayed strains under a constant load. These deformations are related to micromechanisms which occur in its microstructure. To model this behaviour, a new numerical multi-scales method is suggested. Based on a method for the calculation of the effective response for a non-aging material, an extensi...

Many researchers have proposed hypotheses concerning the physical mechanisms that govern creep and among them the development of microcracks is well recognized. For high load levels, microcracking may initiates at the moment of load application and begins to grow to form a time-dependent crack path. An experimental investigation is proposed here in...

In this paper, the fracture characteristics of concrete at very early ages are investigated. Experimentally , three point bending tests are performed on notched beams at very early-ages (before 24 h) and the Load-CMOD curves are obtained. In order to find the trend of the evolution of the fracture energy, an inverse analysis procedure is developed....

In order to build sustainable structures, the study of mechanical behavior must integrate with local phenomena, e.g. fracture and strain localization. The fracture usually develops in the form of main crack, with branches, secondary cracks and the microcracking zone ahead. Various experimental methods are already employed to detect the fracture pro...

In its service-life concrete is loaded and delayed strains appear due to creep phe- nomenon. Some theories suggest that micro-cracks nucleate and grow when concrete is submitted to a high sustained loading, thereby contributing to the weakening of concrete. Thus, it is important to understand the interaction between the viscoelastic deformation and...

In order to design reliable concrete structures, prediction of long term behaviour of concrete is important. In fact, creep deformation can cause mechanical deterioration and cracking, stress redistribution, loss in presteressed members and rarely ruin the structure. The aim of this research is to have a better understing of the interaction between...

In order to design reliable concrete struc-tures, prediction of long term behaviour of concrete is important by considering a coupling between creep and damage. An experimental investigation on the fracture properties of concrete beams submitted to creep bending tests with high levels of sustained load is reported. The influence of creep on the res...

In its service-life concrete is loaded and delayed strains appear due to creep phenomenon. Some theories suggest that micro-cracks nucleate and grow up when concrete is submitted to a high sustained loading, which contribute to make the concrete weaker. Thus, it is important to understand the interaction between the viscoelastic deformation and...

The use of shrinkage-reducing admixtures (SRA) has been suggested to improve concrete performance in terms of lower risk of cracking related to drying shrinkage. Various forms of SRA are commercially available and they may act through different mechanisms. Some SRA mainly acts on drying and weight loss leading to shrinkage. In this paper, the influ...

Creep and damage in concrete govern the long-term deformability of concrete. Thus, it is important to understand the interaction between creep and damage in order to design reliable civil engineering structures subjected to high level loading during a long time. Many investigations have been performed on the influence of concrete mixture, the effec...