Browsing by Author "Kheddache, Lynda"

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    Effect of Fiber Distribution on the Mechanical Behavior in Bending of Self-Compacting Mortars
    (Sciendo, 2020) Kheddache, Lynda; Chahour, Kahina; Safi, Brahim
    The purpose of this work is to assess the steel fiber distribution effect on physical and mechanical properties of self-compacting mortar. An experimental study was conducted to see the fiber distribution during the implementation of self-compacting mortars that are fluid and on mechanical behavior in bending tensile strength. A method of placing self-compacting mortar in the molds has been developed to highlight the distribution of fibers in the cementitious matrix. The mortars are placed in prismatic molds in three layers. The amount of steel fibers differs from one layer to another. A total quantity of 90 kg /m3 was distributed in prismatic molds of dimensions 40x40x160 mm3. Straight and hooked ends steel fibers were used. The characteristics of mortars containing both types of fibers in the fresh and hardened state were measured and compared to those of self-compacting mortar without fibers. The pouring by layer allowed us to deduce that the distribution of metallic fibers has a significant effect on the hardened properties of the mortar. Indeed, the mechanical strength of the fiber-reinforced mortar depends on the nature and distribution of fibers in the cementitious matrix (mortar). A gain in bending tensile strength of 71.83% was recorded for self-compacting mortars elaborated with hooked end fibers and 52.11% for those containing straight steel fibers. Indeed, mortars containing entirely the same dosage of steel fibers (90 kg/m3) have a bending tensile strength that varies according to the fibers dosage by layers. Mortar samples with higher fiber content in the lower layer have a higher bending tensile strength than other samples with a higher fiber layer in the middle or layer above. However, it should be noted that steel fibers with hooks are much more effective than those without hooks. Indeed, the effect of fiber distribution is more significant for fibers without hooks because the hooks can slow down the movement of the fibers during the pouring of the mortar. The variation of the dosages per layer generated a difference in the deflection values for the mortars. The deflection is much higher for fiber-reinforced mortars (with hooks) compared to fiber-reinforced mortars without hooks
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    Effet du dosage et de la repartition des fibres Metalliques sur le comportement mecanique en flexion Des mortiers autoplacants fibres
    (2019) Kheddache, Lynda; Chahour, Kahina; Safi, Brahim
    Ce travail décrit l'influence du dosage et la répartition des fibres métalliques sur le comportement en traction par flexion des mortiers autoplaçants fibrés. Des essais de flexion trois points ont été réalisés sur des éprouvettes prismatiques de dimensions 40x40x160 mm à l'âge de 28 jours, en faisant varier la quantité (20, 30 et 40 kg/m3) et la répartition des fibres métalliques. Les résultats obtenus ont montré que la résistance à la traction par flexion est d'autant plus importante que le dosage en fibres est important. Par ailleurs, l'effet de la répartition des fibres a été mis en évidence, puisque un gain de la résistance allant jusqu'à 50 % a été obtenu, comparé au mortier autoplaçant sans fibres
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    Highlighting of the distribution effect of steel hook fibers at low and high dosage on the flexural strength of self-compacting mortars
    (2022) Kheddache, Lynda; Aribi, Chouaib; Chahour, Kahina; Safi, Brahim
    In this paper, the distribution effect of low and high dosage steel hooked fibers on the flexural strength and mechanical behaviour of self-compacting mortars is investigated. Specimens were shaped so as to distribute the steel hooked fibers in three layers at different dosage (volume fraction of 0.25%, 0.40% and 0.50% respectively for each layer). The obtained results show that the mechanical behaviour in flexural and the flexural strength of the reinforced self-consolidating mortars were significantly influenced and directly depending on the fibers distribution per layer. This finding clearly shows the importance of the steel fibers distribution in the cement matrix during implementation has a major influence on the mechanical behaviour of mortars reinforced with metal fibers. The maximum value recorded is 14.5 MPa for the high dosage. The distribution of the steel fibers by layer made it possible to obtain a strength gain of 71.83% at low dosage and more than 100% at high dosage
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    Modélisation et caractérisation expérimentale du comportement en flexion des mortiers et bétons autoplaçants fibrés (fibres métalliques) : influence du dosage et de la répartition des fibres
    (Université M'Hamed Bougara Boumerdès : Faculté de Technologie, 2023) Kheddache, Lynda; Safi, Brahim(Directeur de thèse)
    Cette thèse a pour but de mettre en évidence l'influence du dosage et de la répartition des fibres sur le comportement en flexion des mortiers et béton autoplaçants et à proposer un model numérique décrivant le comportement en flexion des mortiers autoplaçants à base de fibres métalliques, tenant en compte l'influence de la répartition des fibres dans la matrice cimentaire. Ce model nous permettra de mieux comprendre l'influence de la mise en œuvre des mortiers fibrés (répartition des fibres) sur la ductilité des structures en béton autoplaçants. La première partie du travail sera consacrée à l'étude expérimentale de l'influence des dosages et la répartition des fibres au sein de la matrice cimentaire sur le comportement en flexion des mortiers et bétons autoplaçants. La seconde partie de travail sera consacrée à la modélisation du comportement mécanique de ces mortiers