Mohamed Chemrouk - Profile on Academia.edu (original) (raw)
Papers by Mohamed Chemrouk
Construction and Building Materials, 2012
This study aims in examining the influence of the paste yield stress and compressive strength on ... more This study aims in examining the influence of the paste yield stress and compressive strength on the behaviour of fibre-reinforced concrete (FRC) versus direct shear. The parameters studied are the steel fibre conten ts, the aspect ratio of fibres and the concrete strength. Prismatic specimens of dimensions 10x10x35cm made of concrete of various yield stress reinforced with steel fibres hooked at the ends with three fibre volume fractions (i.e. 0, 0.5 and 1%) and two aspects ratio (65 and 80) were tested to direct shear. Three types of concretes with various compressive strength and yield stress were tested, an ordinary concrete (OC), a self -compacting concrete (SCC) and a high strength concrete (HSC). The concrete strengths investigated include 30 MPa for OC, 60 MPa for SCC and 80 MPa for HSC. The results show that the shear strength and ductility are affected and have been improved very significantly by the fibre contents, fibre aspect ratio and concrete strength. As the compressive strength and the volume fraction of fibres increase, the shear strength increases. However, yield stress of concrete has an important influence on the orientation and distribution of the fibres in the matrix. The ductility was much higher fo r ordinary and selfcompacting concretes (concrete with good workability). The ductility in direct shear depends on the fibre orientation and is significantly improved when the fibres are perpendicular to the shear plane. On the contrary, for concrete with poor workability, an inadequate distribution and orientation of fibres occurred, leading to a weak contribution of the fibres to the direct shear behaviour.
Advances in Structural Engineering, 2010
The paper describes a study in which sixteen reinforced concrete beams without transverse stirrup... more The paper describes a study in which sixteen reinforced concrete beams without transverse stirrups were tested to failure to investigate the influences of the shear-span/depth ratio ( a/d), the longitudinal steel ratio (ρ) and the compressive strength of concrete ( f'c) on the global behaviour in shear for beams made of normal strength concrete (NSC) as well as high strength concrete (HSC). Crack development and propagation were studied through continuous monitoring of the shear cracking using digital video recording. The test results show that the shear capacity depends more on the shear-span/depth ratio ( a/d) and the longitudinal steel ratio (ρ) and relatively less so on the compressive strength ( f'c) in the case of HSC. Based on this study and on data collected from the literature, a proposition for computing the shear stength of concrete beams without stirrups is made; it covers compressive strengths in the range of 40 MPa to 104 MPa. Using the proposed shear formulae,...
This work reports on an experimental investigation dealing with the effects of transverse reinfor... more This work reports on an experimental investigation dealing with the effects of transverse reinforcement, in the form of stirrups, on the behaviour under load of high performances concrete (HPC) beams. The crack patterns and crack widths, the failure modes, the shear strengths and the ductility of HPC beams containing transverse stirrups were assessed and compared to those in ordinary concrete beams. The test results show that the use of transverse reinforcement in the form of stirrups restrains efficiently the inclined cracking and enhances the aggregate interlocking, known to be weaker in HPC without transverse reinforcement, and thus improves the shear strength of HPC beams. They also improve the contribution of the main longitudinal reinforcement to the shear strength through the dowel action. Finally, the transverse reinforcement improves appreciably the ductility of HPC beams at the ultimate state. In some cases, they changed the failure mode from a brittle shear to a markedly ductile flexure with an increased ultimate carrying capacity. The test results concerning the transverse reinforcement contribution to the shear strength are compared with those predicted by Eurocode 2. The comparison reveals a considerable overestimation of the contribution of the transverse reinforcement to the shear strength of HPC beams by the Eurocode 2. This reduces the safety margin required against shear failure, often catastrophic, and may even lead to unsafe shear design for high performances concrete.
Influence de la rhéologie des bétons renforcés de fibres métalliques sur leurs propriétés mécaniques
Revue européenne de génie civil, 2009
Advances in Structural Engineering, 2012
This paper presents the results of an experimental investigation dealing with the effects of tran... more This paper presents the results of an experimental investigation dealing with the effects of transverse reinforcement on the crack patterns, the ultimate carrying capacity and the ductility of beams made of high strength concrete and normal strength concrete for comparison purposes. The test results are analyzed and compared with the shear provisions in the four major universal codes (ACI-318; BS-8110; Eurocode 2; BAEL 99). Twenty six reinforced concrete beams with and without transverse reinforcement were constructed using different shear-span to depth ratios (a/d = 1.5, 2.0 and 3.0) and different compressive strengths of concrete (44 MPa, 65 MPa and 86 MPa). The test results indicate that the presence of transverse reinforcement had controlled efficiently the crack width by enhancing the aggregate interlocking on the crack surface, increased moderately the shear strengths of the beams by factors ranging from 1.14 to 1.86, and increased appreciably the ductility of beams at the ult...
RESUME. L'objectif de cet article est d'etudier l'effet de la resistance du beton et ... more RESUME. L'objectif de cet article est d'etudier l'effet de la resistance du beton et la presence des fibres metalliques sur la resistance au fendage et la ductilite des betons fibres. Les principaux parametres du programme d'essai sont : la resistance a la compression, le dosage et elancement (longueur/diametre) des fibres. Les resultats montrent que la presence des fibres et la resistance a la compression du beton ont un effet significatif sur le comportement du beton fibre au fendage. Les fibres se sont averees plus efficaces dans les matrices a hautes resistances, en augmentant a la fois la charge ultime et la ductilite. Cette augmentation est attribuee a la bonne qualite d'adherence entre les fibres et la matrice; une augmentation allant jusqu'a 70% a ete enregistree. Les resultats montrent l'existence de deux mecanismes de rupture, le premier est associe a une fissure centrale, le second a des fissures secondaires initiees au niveau des bandes de cha...
CFRP confinement effectiveness on the behavior of reinforced concrete columns with respect to buckling instability
Construction and Building Materials, 2015
ABSTRACT This research aims to demonstrate the effectiveness of confinement with a composite carb... more ABSTRACT This research aims to demonstrate the effectiveness of confinement with a composite carbon fiber on reducing buckling instabilities, and highlight the changes in behavior of slender columns of reinforced concrete. For this purpose, an experimental study on six square-section slender reinforced concrete columns is conducted. The columns were confined by single-layer wraps of carbon fiber composites. They were tested under a doubly eccentric compressive load. The resulting tests were illustrated by the load–deflection, load–moment and moment–curvature responses and bending moment–axial force diagrams. Various characteristics such as strength, stiffness, ductility, the ability to absorb the energy of deformation were discussed.
The Deteriorations of Reinforced Concrete and the Option of High Performances Reinforced Concrete
Procedia Engineering, 2015
Flexural behaviour of steel fibre-reinforced concrete under cyclic loading
Construction and Building Materials, 2016
The objective of this experimental investigation is the study of the mechanical performance of po... more The objective of this experimental investigation is the study of the mechanical performance of polypropylene fibre concretes. The fibres used in this work are coming from an industrial waste which results from the fabrication of domestic brushes and sweeps. The length of the fibres is 50mm and their dosage is 0.5% by weight. The obtained results confirmed the efficiency of the polypropylene fibers on the amelioration of the flexural tensile and splitting strength of concrete, the percentage of this amelioration at 28 ages is about 14% and 49% respectively compared to the concrete without fibres. The behaviour of concrete beams with longitudinal reinforcement is clearly improved by the addition of polypropylene fibres, the flexural strength in fibrous beams is increased by almost 24% compared to beams without fibres.
Déchets, sciences et techniques, 2010
Laghouat region (situated in the south Algeria) is among the parts of Algeria which have a large ... more Laghouat region (situated in the south Algeria) is among the parts of Algeria which have a large natural limestone deposit, which extends over the totality of the southern side of the Saharan Atlas. The exploitation of this material in the industry of coarse aggregates generates significant amounts of fine residues, currently badly or less exploited and meanwhile causes harm to the environment. In order to valorise this waste material and met the environmental requirements, the idea is to exploit these residues as limestone fine aggregate for concrete. Beside for enhancing the mechanical properties of concrete and exploit polypropylene fibres wastes resulting from the industry of brushes and sweep domestic, we decide to incorporate them in the limestone mortar.
Efficacité du renforcement des poutres en béton armé par des matériaux composites
MATEC Web of Conferences, 2012
TRANSVERSE REINFORCEMENT EFFECTS ON THE LOADING BEHAVIOUR OF HIGH PERFORMANCES CONCRETE BEAMS
Comportement des bétons fibrés à la flexion: influence des fibres et de la résistance à la compression
Comportement de poutres en béton ordinaire et en béton à hautes performances vis-à-vis de la flexion
Influence of the rheology of fiber reinforced concretes on their mechanical properties
Effectiveness of Composite CFRP Confinement on Very Slender Reinforced Concrete Columns
Study of the Reinforcement of Limestone Mortars by Polypropylene Fibers Waste
Physics Procedia, 2011
ABSTRACT The first objective of this study is the valorisation of limestone waste produced from t... more ABSTRACT The first objective of this study is the valorisation of limestone waste produced from the crushing stations by using it as fine sand for mortars mixes and hence replaces the river sand. The second objective of this research is the reinforcement of mortars by polypropylene fibers waste coming from the fabrication of domestic brushes and sweeps. Due to their low weight, high deformation rate and does not react with cement elements, the polypropylene fibers are among the most used one for the reinforcement of concretes. In this paper we presented the results of physical and-mechanical properties of reinforced mortars prepared with limestone sand which is in abundance in the city of Laghouat situated in 400km in the South of the capital of Algeria (Algiers). The fibers dosages used are: 0.5, 1, 2 and 4wt% with length of 10, 20 and 30mm. The results of this investigation put in evidence the efficiency of the reinforcement of limestone mortars by polypropylene fibers waste in the improvement of their flexural tensile and compression strength.
Behaviour of polypropylene fibre mortars conserved in different environments
European Journal of Environmental and Civil Engineering, 2013
Revue européenne de génie civil, 2009
Ce papier présente les résultats d'une étude expérimentale sur l'influence de la rhéologie sur l'... more Ce papier présente les résultats d'une étude expérimentale sur l'influence de la rhéologie sur l'orientation des fibres métalliques et par suite sur le comportement en flexion et compression des bétons de fibres. Plus précisément, on étudie l'influence de l'orientation d'un volume de 0.5 % de fibres sur les propriétés mécaniques d'un béton ordinaire fluide, d'un béton autoplaçant (seuil de cisaillement faible < 50 Pa) et d'un béton à hautes performances plastiques (seuil de cisaillement élevé >100 Pa).
Construction and Building Materials, 2012
This study aims in examining the influence of the paste yield stress and compressive strength on ... more This study aims in examining the influence of the paste yield stress and compressive strength on the behaviour of fibre-reinforced concrete (FRC) versus direct shear. The parameters studied are the steel fibre conten ts, the aspect ratio of fibres and the concrete strength. Prismatic specimens of dimensions 10x10x35cm made of concrete of various yield stress reinforced with steel fibres hooked at the ends with three fibre volume fractions (i.e. 0, 0.5 and 1%) and two aspects ratio (65 and 80) were tested to direct shear. Three types of concretes with various compressive strength and yield stress were tested, an ordinary concrete (OC), a self -compacting concrete (SCC) and a high strength concrete (HSC). The concrete strengths investigated include 30 MPa for OC, 60 MPa for SCC and 80 MPa for HSC. The results show that the shear strength and ductility are affected and have been improved very significantly by the fibre contents, fibre aspect ratio and concrete strength. As the compressive strength and the volume fraction of fibres increase, the shear strength increases. However, yield stress of concrete has an important influence on the orientation and distribution of the fibres in the matrix. The ductility was much higher fo r ordinary and selfcompacting concretes (concrete with good workability). The ductility in direct shear depends on the fibre orientation and is significantly improved when the fibres are perpendicular to the shear plane. On the contrary, for concrete with poor workability, an inadequate distribution and orientation of fibres occurred, leading to a weak contribution of the fibres to the direct shear behaviour.
Advances in Structural Engineering, 2010
The paper describes a study in which sixteen reinforced concrete beams without transverse stirrup... more The paper describes a study in which sixteen reinforced concrete beams without transverse stirrups were tested to failure to investigate the influences of the shear-span/depth ratio ( a/d), the longitudinal steel ratio (ρ) and the compressive strength of concrete ( f'c) on the global behaviour in shear for beams made of normal strength concrete (NSC) as well as high strength concrete (HSC). Crack development and propagation were studied through continuous monitoring of the shear cracking using digital video recording. The test results show that the shear capacity depends more on the shear-span/depth ratio ( a/d) and the longitudinal steel ratio (ρ) and relatively less so on the compressive strength ( f'c) in the case of HSC. Based on this study and on data collected from the literature, a proposition for computing the shear stength of concrete beams without stirrups is made; it covers compressive strengths in the range of 40 MPa to 104 MPa. Using the proposed shear formulae,...
This work reports on an experimental investigation dealing with the effects of transverse reinfor... more This work reports on an experimental investigation dealing with the effects of transverse reinforcement, in the form of stirrups, on the behaviour under load of high performances concrete (HPC) beams. The crack patterns and crack widths, the failure modes, the shear strengths and the ductility of HPC beams containing transverse stirrups were assessed and compared to those in ordinary concrete beams. The test results show that the use of transverse reinforcement in the form of stirrups restrains efficiently the inclined cracking and enhances the aggregate interlocking, known to be weaker in HPC without transverse reinforcement, and thus improves the shear strength of HPC beams. They also improve the contribution of the main longitudinal reinforcement to the shear strength through the dowel action. Finally, the transverse reinforcement improves appreciably the ductility of HPC beams at the ultimate state. In some cases, they changed the failure mode from a brittle shear to a markedly ductile flexure with an increased ultimate carrying capacity. The test results concerning the transverse reinforcement contribution to the shear strength are compared with those predicted by Eurocode 2. The comparison reveals a considerable overestimation of the contribution of the transverse reinforcement to the shear strength of HPC beams by the Eurocode 2. This reduces the safety margin required against shear failure, often catastrophic, and may even lead to unsafe shear design for high performances concrete.
Influence de la rhéologie des bétons renforcés de fibres métalliques sur leurs propriétés mécaniques
Revue européenne de génie civil, 2009
Advances in Structural Engineering, 2012
This paper presents the results of an experimental investigation dealing with the effects of tran... more This paper presents the results of an experimental investigation dealing with the effects of transverse reinforcement on the crack patterns, the ultimate carrying capacity and the ductility of beams made of high strength concrete and normal strength concrete for comparison purposes. The test results are analyzed and compared with the shear provisions in the four major universal codes (ACI-318; BS-8110; Eurocode 2; BAEL 99). Twenty six reinforced concrete beams with and without transverse reinforcement were constructed using different shear-span to depth ratios (a/d = 1.5, 2.0 and 3.0) and different compressive strengths of concrete (44 MPa, 65 MPa and 86 MPa). The test results indicate that the presence of transverse reinforcement had controlled efficiently the crack width by enhancing the aggregate interlocking on the crack surface, increased moderately the shear strengths of the beams by factors ranging from 1.14 to 1.86, and increased appreciably the ductility of beams at the ult...
RESUME. L'objectif de cet article est d'etudier l'effet de la resistance du beton et ... more RESUME. L'objectif de cet article est d'etudier l'effet de la resistance du beton et la presence des fibres metalliques sur la resistance au fendage et la ductilite des betons fibres. Les principaux parametres du programme d'essai sont : la resistance a la compression, le dosage et elancement (longueur/diametre) des fibres. Les resultats montrent que la presence des fibres et la resistance a la compression du beton ont un effet significatif sur le comportement du beton fibre au fendage. Les fibres se sont averees plus efficaces dans les matrices a hautes resistances, en augmentant a la fois la charge ultime et la ductilite. Cette augmentation est attribuee a la bonne qualite d'adherence entre les fibres et la matrice; une augmentation allant jusqu'a 70% a ete enregistree. Les resultats montrent l'existence de deux mecanismes de rupture, le premier est associe a une fissure centrale, le second a des fissures secondaires initiees au niveau des bandes de cha...
CFRP confinement effectiveness on the behavior of reinforced concrete columns with respect to buckling instability
Construction and Building Materials, 2015
ABSTRACT This research aims to demonstrate the effectiveness of confinement with a composite carb... more ABSTRACT This research aims to demonstrate the effectiveness of confinement with a composite carbon fiber on reducing buckling instabilities, and highlight the changes in behavior of slender columns of reinforced concrete. For this purpose, an experimental study on six square-section slender reinforced concrete columns is conducted. The columns were confined by single-layer wraps of carbon fiber composites. They were tested under a doubly eccentric compressive load. The resulting tests were illustrated by the load–deflection, load–moment and moment–curvature responses and bending moment–axial force diagrams. Various characteristics such as strength, stiffness, ductility, the ability to absorb the energy of deformation were discussed.
The Deteriorations of Reinforced Concrete and the Option of High Performances Reinforced Concrete
Procedia Engineering, 2015
Flexural behaviour of steel fibre-reinforced concrete under cyclic loading
Construction and Building Materials, 2016
The objective of this experimental investigation is the study of the mechanical performance of po... more The objective of this experimental investigation is the study of the mechanical performance of polypropylene fibre concretes. The fibres used in this work are coming from an industrial waste which results from the fabrication of domestic brushes and sweeps. The length of the fibres is 50mm and their dosage is 0.5% by weight. The obtained results confirmed the efficiency of the polypropylene fibers on the amelioration of the flexural tensile and splitting strength of concrete, the percentage of this amelioration at 28 ages is about 14% and 49% respectively compared to the concrete without fibres. The behaviour of concrete beams with longitudinal reinforcement is clearly improved by the addition of polypropylene fibres, the flexural strength in fibrous beams is increased by almost 24% compared to beams without fibres.
Déchets, sciences et techniques, 2010
Laghouat region (situated in the south Algeria) is among the parts of Algeria which have a large ... more Laghouat region (situated in the south Algeria) is among the parts of Algeria which have a large natural limestone deposit, which extends over the totality of the southern side of the Saharan Atlas. The exploitation of this material in the industry of coarse aggregates generates significant amounts of fine residues, currently badly or less exploited and meanwhile causes harm to the environment. In order to valorise this waste material and met the environmental requirements, the idea is to exploit these residues as limestone fine aggregate for concrete. Beside for enhancing the mechanical properties of concrete and exploit polypropylene fibres wastes resulting from the industry of brushes and sweep domestic, we decide to incorporate them in the limestone mortar.
Efficacité du renforcement des poutres en béton armé par des matériaux composites
MATEC Web of Conferences, 2012
TRANSVERSE REINFORCEMENT EFFECTS ON THE LOADING BEHAVIOUR OF HIGH PERFORMANCES CONCRETE BEAMS
Comportement des bétons fibrés à la flexion: influence des fibres et de la résistance à la compression
Comportement de poutres en béton ordinaire et en béton à hautes performances vis-à-vis de la flexion
Influence of the rheology of fiber reinforced concretes on their mechanical properties
Effectiveness of Composite CFRP Confinement on Very Slender Reinforced Concrete Columns
Study of the Reinforcement of Limestone Mortars by Polypropylene Fibers Waste
Physics Procedia, 2011
ABSTRACT The first objective of this study is the valorisation of limestone waste produced from t... more ABSTRACT The first objective of this study is the valorisation of limestone waste produced from the crushing stations by using it as fine sand for mortars mixes and hence replaces the river sand. The second objective of this research is the reinforcement of mortars by polypropylene fibers waste coming from the fabrication of domestic brushes and sweeps. Due to their low weight, high deformation rate and does not react with cement elements, the polypropylene fibers are among the most used one for the reinforcement of concretes. In this paper we presented the results of physical and-mechanical properties of reinforced mortars prepared with limestone sand which is in abundance in the city of Laghouat situated in 400km in the South of the capital of Algeria (Algiers). The fibers dosages used are: 0.5, 1, 2 and 4wt% with length of 10, 20 and 30mm. The results of this investigation put in evidence the efficiency of the reinforcement of limestone mortars by polypropylene fibers waste in the improvement of their flexural tensile and compression strength.
Behaviour of polypropylene fibre mortars conserved in different environments
European Journal of Environmental and Civil Engineering, 2013
Revue européenne de génie civil, 2009
Ce papier présente les résultats d'une étude expérimentale sur l'influence de la rhéologie sur l'... more Ce papier présente les résultats d'une étude expérimentale sur l'influence de la rhéologie sur l'orientation des fibres métalliques et par suite sur le comportement en flexion et compression des bétons de fibres. Plus précisément, on étudie l'influence de l'orientation d'un volume de 0.5 % de fibres sur les propriétés mécaniques d'un béton ordinaire fluide, d'un béton autoplaçant (seuil de cisaillement faible < 50 Pa) et d'un béton à hautes performances plastiques (seuil de cisaillement élevé >100 Pa).