Browsing by Author "Chahour, Kahina"

Now showing 1 - 9 of 9

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
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
Granulated foam glass based on mineral wastes used for building materials
(SAGE, 2017) Chahour, Kahina; Aboutaleb, Djamila; Safi, Brahim; Mazari, Tassadit; Zeghad, Mohamed
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
Mechanical behavior and chemical durability of marble-based mortar: Application to panels subjected to punching
(Elsevier, 2019) Chahour, Kahina; Safi, Brahim
The main purpose of this paper is to use marble as sand in the mortar composition and to study the impact of natural sand replacement on mortar properties, such as mechanical strength, rheology and durability of different mortar mixtures at different curing ages up to 56 days. Natural sand (NS) was substituted by marble sand at different percentages (0%, 30%, 50%, 70% and 100% by weight of NS). The fresh property (workability), hardened properties (compressive, flexural and punching strength), compactness (ultrasonic wave speed) and durability (acid and water resistance) of the mortars studied were evaluated. A complementary study on mechanical behavior of panels elaborated with the studied mortars has been conducted; the test results have shown that mortar with 50% and 100% of substitution rate give better results for compactness, compressive and flexural strength. The punching strength obtained by the punching shear test has been significantly improved by the increase of natural sand substitution rate. However, panels carried out marble-based mortars with 70% of marble sand have given a punching strength similar to that obtained by control mortar panel (100% natural sand). This result has been also proven by the improvement of the mechanical behavior of slab made with 100% marble mortar. Results of durability estimated by acid attack have shown that loss in weight of mortar mixtures decreases with the increase of the percentage marble sand. Whereas, beyond 50% of marble sand content, water permeability increases compared to that of mortar control
Physico-mechanical characterization of an ecological marble based- mortar
(STEF92 Technology, 2023) Chahour, Kahina; Safi, Brahim
Disposal of waste generated by the industries remains one of the major challenges to preserve the environment. Indeed, the use of industrial waste and by-products in construction is an important advantage to conserve natural resources. For this reason, several studies have focused on the use of marble waste in construction as recycled aggregate or fine powder. The work aim is to investigate the physical properties and mechanical behavior of eco-friendly mortar made with marble powder. The experimental study consists in studying the effect of cement substitution by marble powder (0%, 5% 10% and 20% wt.) on the fluidity and mechanical properties (Flexural strength, compressive strength and mechanical behavior) of elaborated mortars. The results show that it is possible to manufacture an ecological mortar having the good mechanical characteristics with marble powder and with local materials with the same basic components as a normal mortar and thus obtaining the same characteristics as those known internationally. The content amount of the marble powder as an addition to the cement is satisfactory to produce an ecological mortar with good resistance and better cement economy.
Recycling of Foundry Sand Wastes in Self-Compacting Mortars: Use as Cementitious Materials and Fine Aggregates
(Sciendo, 2020) Sebki, Ghania; Safi, Brahim; Chahour, Kahina
This work aims to study the possibility recycling of foundry sand wastes (FSW) as a cementations additive and fine aggregate in selfcompacting mortars (SCM). For this, an experimental study was carried out to evaluate physical and mechanical properties of SCM. Firstly, sand is substituted by the foundry sand waste at dosages (0%, 10%, 30%, and 50%) by weight of the sand. Secondly cement is partially substituted by crushed foundry sand waste at different ratio (0%, 10%, 20%, 30%, and 50%) by weight of cement. The obtained results show that up to 50%, (FSW) can be used as fine aggregate for mortars without affecting the essential proprieties of mortar. However, beyond 50% of sand substitution, mortars lose their fluidity. The compressive strength of the mortars with 50% of cement substitution decreased compared to the control mortar. Value of the highest compressive strength recorded at 28 days, is of the order of 50 MPa for the mortar with 20% of cement substitution. Also, stress-strain curve show an acceptable mechanical behavior of FSW-based mortar at 50% of sand substitution
RHEOLOGICAL AND MECHANICAL BEHAVIOR STUDY OF ECO-FRIENDLY CEMENT MORTAR MADE WITH MARBLE POWDER
(University of Zielona Gora, 2024) Chahour, Kahina; Mechakra, Hamza; Safi, Brahim; Dehbi, Nacera-Melissa; Chaibet, Cylia
The work aim is to investigate the rheological and mechanical behavior of an eco-friendly mortar made with marble powder. Marble is have used as sand (total substitution of natural sand) and as an additional material (partial substitution of cement). Firstly, rheological tests were carried out on the cement pastes in order to study the effect of cement substitution by marble powder on the rheological behavior. Secondly, our study is devoted to evaluate the mechanical performances (flexural strength, compressive strength, mechanical behavior and ultrasonic pulse velocity) of a fluid mortar such as the case of the self-compacting mortars elaborated with the marble powder as an addition a material and as sand. The mechanical test results show that compressive strength and mechanical behavior of an ecological cement mortar made with marble waste as natural sand improved significantly. However, marble-based mortars with 100% of marble sand have given a mechanical strength similar to that obtained by control cement mortar (100% natural sand). It was also noted that it an ecological cement mortar made with 30% of marble powder as an addition a supplementary material can be obtained. This leads to a reduction in cement consumption and a reduction in CO2 gas emissions caused by cement production.
Use of refractory bricks as sand replacement in self-compacting mortar
(Taylor & Francis Online, 2017) Aboutaleb, Djamila; Safi, Brahim; Chahour, Kahina; Belaid, Amrane
This present work investigate the possibility of using refractory bricks (RB) as fine aggregates (by partial and total substitution of natural sand) in self-compacting mortars (SMCs). For this, an experimental study was carried out to evaluate physical and mechanical properties ((bulk density, compressive and flexural strength) of the self-compacting mortars (SCMs) with partial and total substitution of natural sand (NS) by crushed refractory bricks (RB) at different ratio (BR/S= 0, 10, 30, 50 et 100%) by weight. The results obtained show that the RB (0/5 mm class), can be used as fine aggregates for self-compacting mortar, without affecting the essential properties of mortar. However, the performances of RB-based mortar (100% as sand), were better and are suitable for a fluid concrete (such as self- compacting concrete)