B. Benmokrane | Université de Sherbrooke (University of Sherbrooke) (original) (raw)

Papers by B. Benmokrane

Research paper thumbnail of Mechanical, Physical and Durability Characterization of Pre- Stressed GFRP Reinforcing Bars

This paper presents the physical and durability characterization of glass fibre-reinforced polyme... more This paper presents the physical and durability characterization of glass fibre-reinforced polymers (GFRP) bars subjected to different tensile stress levels. GFRP bars were first loaded at levels up to 20, 40, 60 and 80 % of their ultimate tensile strength (UTS) to simulate the effect of an impact collision which can create cracks and microcracks in the FRP bars and affect the long-term durability of the product. The experimental results showed that the loading of GFRP bars did not have a dramatic effect on the durability of the bars even when a pronounced tensile stress (80 % UTS approx) was in place.

Research paper thumbnail of Mechanisms of shear resistance of one-way concrete slabs reinforced with FRP bars

Construction and Building Materials, 2016

h i g h l i g h t s We investigate the shear behavior of one-way FRP-reinforced concrete slabs. S... more h i g h l i g h t s We investigate the shear behavior of one-way FRP-reinforced concrete slabs. Shear behavior depends on the axial stiffness of FRP bars. We investigate the shear capacity of slabs using normal and high strength concretes. We assess the shear behavior in terms of crack patterns, and shear capacities.

Research paper thumbnail of Strength of circular HSC columns reinforced internally with carbon-fiber-reinforced polymer bars under axial and eccentric loads

Construction and Building Materials, 2017

Behavior and failure mechanisms of circular HSC columns reinforced with CFRP bars and spirals und... more Behavior and failure mechanisms of circular HSC columns reinforced with CFRP bars and spirals under eccentric loads are presented. The performance of CFRP bars in compression is assessed. A detailed sectional analysis for predicting the axial force and bending moment at different load eccentricity is introduced. The P-M interaction diagrams encompassing different parameters are developed.

Research paper thumbnail of Experimental testing of basalt-fiber-reinforced polymer bars in concrete beams

Composites Part B: Engineering, 2016

The advances in fiber-reinforced-polymer (FRP) technology have spurred interest in introducing ne... more The advances in fiber-reinforced-polymer (FRP) technology have spurred interest in introducing new fibers, such as basalt, in addition to the commonly used glass, carbon, and aramid. Recently, new basalt-FRP (BFRP) bars have been developed, but research is needed to characterize and understand how BFRP bars would behave in concrete members. This paper presents an experimental study aimed at determining the bond-dependent coefficient (k b) and investigating the structural performance of newly developed BFRPs in concrete beams. A total of six concrete beams reinforced with BFRP bars were built and tested up to failure. The test beams measured 200 mm wide, 300 mm high, and 3100 mm long. Ten, 12, and 16 mm BFRP bars with sandcoated surfaces over helical wrapping were used. The beam specimens were designed in accordance with Annex S of CSA S806-12 and tested under four-point bending over a clear span of 2700 mm until failure. The beam test results are introduced and discussed in terms of cracking behavior, deflection, and failure modes. The test results yielded an average k b of 0.76, which is in agreement with the CSA S6-14 recommendation of 0.8 for sand-coated bars. Moreover, comparing the results to code provisions showed that CSA S806-12 may yield reasonable yet conservative deflection predictions at service load for the beams reinforced with BFRP bars.

Research paper thumbnail of Distribution expérimentale des contraintes le long d'ancrages scellés dans un massif rocheux soumis à des charges de tenionnement

Research paper thumbnail of Durability of Tokyo Rope carbon cables in alkaline environment

Research paper thumbnail of Physical and mechanical characteristics of new basalt-FRP bars for reinforcing concrete structures

Construction and Building Materials, 2015

h i g h l i g h t s Physical and mechanical characterization of newly developed basalt FRP bars f... more h i g h l i g h t s Physical and mechanical characterization of newly developed basalt FRP bars for concrete members. Durability of BFRP bars in harsh alkaline conditions simulating the concrete environment. Discussion of BFRP characterization and durability results and compare them against the requirements of FRP standards.

Research paper thumbnail of Construction, instrumentation et essais d’une dalle de tablier de pont en béton armé de PRFV conçue avec la méthode empirique

La dégradation des dalles de tabliers en béton est un problème très répandu dans les ponts du Can... more La dégradation des dalles de tabliers en béton est un problème très répandu dans les ponts du Canada et dans le monde entier. Cette dégradation est principalement causée par la corrosion des armatures d’acier dans le béton. Cette corrosion est accélérée par l’application de sel de déglaçage durant les mois d’hiver ou par un environnement agressif. Les armatures en polymères renforcés de fibres (PRF) constituent une solution afin de contrer la dégradation prématurée et coûteuse de ces structures. De nombreuses études et recherches ont été réalisées avec ce type de matériau au cours des dernières années. De plus, des armatures de PRF ont été utilisées dans la construction de plusieurs ponts routiers au Québec, au Canada et aux États-Unis. Dans le cas des dalles de tablier sur poutre, le Code canadien sur le calcul des ponts routiers (CAN/CSA S6) permet l’utilisation de la méthode empirique pour la conception de dalles armées de PRF. Toutefois, depuis son adoption dans l’édition de 200...

Research paper thumbnail of Degradation Assessment of Internal Continuous Fiber Reinforcement in Concrete Environment

The Fiber Reinforced Polymer properties include high strength-to-weight ratio, high stiffness-to-... more The Fiber Reinforced Polymer properties include high strength-to-weight ratio, high stiffness-to-weight ratio, high-energy absorption, and outstanding corrosion and fatigue damage resistance. Therefore, the use of continuous basalt, glass, and carbon fiber reinforcement in concrete structural applications seems to be promising for reinforcing new concrete structures and strengthening applications. The main objective of this study was to evaluate the characteristics of glass fiber reinforced polymer (GFRP) bars, basalt fiber reinforced polymer (BFRP) reinforcing and prestressing bars, and carbon fiber composite prestressing cables. The test variables included the tensile strength, the modulus of elasticity, behavior, and durability under severe environmental exposures. The study investigated the physical and mechanical properties, durability, and bond strength to concrete of the FRP composites. In addition, the investigators tested concrete beams and slabs reinforced with basalt (BFR...

Research paper thumbnail of Evaluation of Shear Behavior for One-Way Concrete Slabs Reinforced with Carbon-FRP Bars

: Nine one-way concrete slabs reinforced with carbon-FRP bars were constructed and tested to fail... more : Nine one-way concrete slabs reinforced with carbon-FRP bars were constructed and tested to failure under two-point loading. The effect of reinforcement ratios, bar diameters, and various concrete compressive strengths were investigated to determine the concrete’s contribution to shear strength. Slab structural behavior in terms of crack patterns, modes of failure, and ultimate capacities were examined. All slabs ultimately failed in shear that caused rupture and complete separation of both parts of the slab. One of the tested slabs, however, formed more main shear-crack branches, yielding progressive post-peak failure, which protected it from experiencing the catastrophic explosive mode of failure as did the other slabs. The results are compared to the concrete-contribution models derived from CSA S806-12, , CSA S6.1S1-06 ACI 440.1R-06, and JSCE97.

Research paper thumbnail of Behaviour of Shear Critical FRP Reinforced Concrete One-Way Slabs

Bridge deck and parking garage slabs are exposed to aggressive environments particularly in the N... more Bridge deck and parking garage slabs are exposed to aggressive environments particularly in the North American regions resulting from the excessive use of de-icing salts. Fiber-reinforced-polymer (FRP) reinforcements have emerged as a practical and sustainable anti-corrosive reinforcing material with superior tensile strength to overcome the corrosion problem. High comfort level and increase use of the material is currently seen. Protection and regulations policies of some Public North American agencies currently include GFRP reinforcing bars as premium reinforcement. Shear behaviour in RC slabs is examined since most of the bridge deck and parking garage slabs are shear-critical. However, there is still no agreement in FRP design codes and guidelines for shear strength equations. Several design code equations are still based on empirical relationships while recent developments are based on shear theories. The complex nature of shear phenomena which is influenced by many parameters,...

Research paper thumbnail of Pullout behaviour of GFRP bars with anchor head in geopolymer concrete

Composite Structures, 2015

The geopolymer concrete internally reinforced with fibre-reinforced polymer (FRP) bars is anticip... more The geopolymer concrete internally reinforced with fibre-reinforced polymer (FRP) bars is anticipated to offer durable, sustainable, and cost-effective civil infrastructures. In this study, the effect of the anchor head on the pullout behaviour of the sand coated glass-fibrereinforced polymer (GFRP) bars embedded in the geopolymer concrete was investigated using a direct pullout test. Straight and headed GFRP bars with different nominal diameters Ø (12.7 mm, 15.9 mm, and 19.0 mm) and embedment lengths l d (0Ø+l ah , 5Ø+l ah , and 10Ø+l ah for headed bars, where l ah stands for the anchor head length, and 5Ø and 10Ø for straight bars) were considered. The results showed that the provision of anchor head is an efficient method to enhance the anchorage capacity of GFRP bars in geopolymer concrete. The anchor heads improved the anchorage of the sand coated GFRP bars by as much as 49% to 77%. Furthermore, the mechanical bearing resistance provided by the anchor head alone resulted in the development of approximately 45% of the GFRP bars' nominal tensile strength. A comparison of the experimental results with the published studies showed that a much higher load is required to pullout the GFRP bars in geopolymer concrete than in Ordinary Portland Cement-based concrete.

Research paper thumbnail of Reinforcement of concrete using fibre-reinforced polymer composites

Durability of Composites for Civil Structural Applications, 2007

... internal reinforcements. Studies by Vijay and Gangarao (1999) indicated that reinforcing bars... more ... internal reinforcements. Studies by Vijay and Gangarao (1999) indicated that reinforcing bars with urethane-modified biphenol vinylester exhibited the lowest vulnerability to different harsh environments. Among unsaturated ...

Research paper thumbnail of Tests Methods to Determine Properties of FRP Rods for Concrete Structures

Composites in Construction, 2001

Research paper thumbnail of PDF (2807 K) - NRC Research Press

Research paper thumbnail of Bond Strength of FRP Rebar Splices

Research paper thumbnail of Caractéristiques mécaniques et élastiques de bétons à haute performance confectionnés avec différents types de gros granulats

Materials and Structures, 1994

Résumé Dans cette étude, on a mis en évidence le rôle que jouent les gros granulats sur les prop... more Résumé Dans cette étude, on a mis en évidence le rôle que jouent les gros granulats sur les propriétés mécaniques et élastiques d'un béton à haute performance. Quatre types de roches, desquelles ont été extraits les gros granulats, ont été sélectionnés. Deux rapports eau/liant de 0,27 et 0,22 ont été utilisés pour la détermination des mélanges des bétons à haute performance.

Research paper thumbnail of Laboratory evaluation of cement-based grouts and grouted rock anchors

International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts, 1995

The paper reports the findings of a laboratory study on six different types of cement-based grout... more The paper reports the findings of a laboratory study on six different types of cement-based grouts and two types of steel rock anchors. The physical and mechanical characteristics of cement grouts employing silica fume, aluminium powder, superplasticizer or sand are compared with those of conventional cement grouts. Pullout tests of grouted, 7-strand steel cable and solid steel threadbar were conducted under similar conditions for different grouts and embedment lengths. From the results obtained, an empirical equation is derived for the estimation of anchor pullout resistance for a given embedment length. A simple trilinear constitutive model for shear bond stress-slip relation at the anchor-grout interface is proposed and discussed.

Research paper thumbnail of Seismic flexural behavior of concrete connections reinforced with CFRP bars and grids

Composite Structures, 2011

ABSTRACT The corrosion of steel reinforcement in concrete and the resulting deterioration of stru... more ABSTRACT The corrosion of steel reinforcement in concrete and the resulting deterioration of structures prompted research on fiber reinforced polymers (FRP) as potential reinforcement for concrete members, for use in new construction. FRPs have more favorable advantages for new concrete buildings subjected to seismic loads particularly in corrosive environment.A comprehensive experimental research program was conducted at Ottawa University in Canada to investigate the behavior of FRP reinforced concrete joints to develop design and detailing requirements for FRP reinforced concrete joints under seismic loading. Three large-scale FRP reinforced concrete structural joints were designed, constructed, and tested under cyclic loading. The specimens were T-shape joints consisting of two columns and one beam representing half portion of the first and the second floor of one-bay reinforced concrete frame, or exterior joint of frames with more than one bay. The columns were subjected to the constant axial load and the beams were under reversed cyclic loading. The reinforcement cage was consisted of CFRP bars as longitudinal reinforcement and CFRP grids as transverse reinforcement. The paper presents the details and results of the experimental programs. The results indicate that FRP reinforcement can be used effectively in new concrete buildings. Photographs taken at the selected stages of loading illustrated the performance of each joint. The hysteretic behavior was presented in terms of force–displacement and moment–drift relationships and other hysteretic relationships. Spacing of CFRP grids and arrangement of longitudinal CFRP bars were the main test parameters.

Research paper thumbnail of Scaling of strength of FRP reinforced concrete beams without shear reinforcement

Among the unresolved issues in the design of structural concrete reinforced with fiber reinforced... more Among the unresolved issues in the design of structural concrete reinforced with fiber reinforced composite (FRP) bars, the understanding of size effect in the reduction of the shear strength of deep beams without shear reinforcement is of fundamental and practical sig- nificance. Size effect accrues primarily from the larger width of diagonal cracks as the effective depth is increased, and has been extensively documented in the case of steel reinforced concrete (RC) through a number of laboratory tests. In FRP RC, the lower longitudinal elastic modulus of the flexural reinforcement results in deeper and wider cracks. Yet, the calibration of any of the current semi-empirical design algorithms is based on test results of beams and one-way slabs with maximum effective depth of 360 mm, which is not representative of relevant large-scale applications. This paper presents and discusses the results of laboratory testing of large-size and scaled FRP RC beams without shear reinforcement, having maximum effective depth of 147, 294 and 883 mm, and effective reinforcement ratio of 0.12% and 0.24%. It is shown that the shear strength of the large-size specimens with less flexural reinforcement decreases on average by 55% compared with the smaller specimens. However, the conservativeness of the current de- sign algorithms generally offsets the size effect. The provisions of the UK Institution of Struc- tural Engineers (ISE) and the Italian National Research Council (CNR) provide the most accu- rate estimates, where the former yields more conservative and consistent results.

Research paper thumbnail of Mechanical, Physical and Durability Characterization of Pre- Stressed GFRP Reinforcing Bars

This paper presents the physical and durability characterization of glass fibre-reinforced polyme... more This paper presents the physical and durability characterization of glass fibre-reinforced polymers (GFRP) bars subjected to different tensile stress levels. GFRP bars were first loaded at levels up to 20, 40, 60 and 80 % of their ultimate tensile strength (UTS) to simulate the effect of an impact collision which can create cracks and microcracks in the FRP bars and affect the long-term durability of the product. The experimental results showed that the loading of GFRP bars did not have a dramatic effect on the durability of the bars even when a pronounced tensile stress (80 % UTS approx) was in place.

Research paper thumbnail of Mechanisms of shear resistance of one-way concrete slabs reinforced with FRP bars

Construction and Building Materials, 2016

h i g h l i g h t s We investigate the shear behavior of one-way FRP-reinforced concrete slabs. S... more h i g h l i g h t s We investigate the shear behavior of one-way FRP-reinforced concrete slabs. Shear behavior depends on the axial stiffness of FRP bars. We investigate the shear capacity of slabs using normal and high strength concretes. We assess the shear behavior in terms of crack patterns, and shear capacities.

Research paper thumbnail of Strength of circular HSC columns reinforced internally with carbon-fiber-reinforced polymer bars under axial and eccentric loads

Construction and Building Materials, 2017

Behavior and failure mechanisms of circular HSC columns reinforced with CFRP bars and spirals und... more Behavior and failure mechanisms of circular HSC columns reinforced with CFRP bars and spirals under eccentric loads are presented. The performance of CFRP bars in compression is assessed. A detailed sectional analysis for predicting the axial force and bending moment at different load eccentricity is introduced. The P-M interaction diagrams encompassing different parameters are developed.

Research paper thumbnail of Experimental testing of basalt-fiber-reinforced polymer bars in concrete beams

Composites Part B: Engineering, 2016

The advances in fiber-reinforced-polymer (FRP) technology have spurred interest in introducing ne... more The advances in fiber-reinforced-polymer (FRP) technology have spurred interest in introducing new fibers, such as basalt, in addition to the commonly used glass, carbon, and aramid. Recently, new basalt-FRP (BFRP) bars have been developed, but research is needed to characterize and understand how BFRP bars would behave in concrete members. This paper presents an experimental study aimed at determining the bond-dependent coefficient (k b) and investigating the structural performance of newly developed BFRPs in concrete beams. A total of six concrete beams reinforced with BFRP bars were built and tested up to failure. The test beams measured 200 mm wide, 300 mm high, and 3100 mm long. Ten, 12, and 16 mm BFRP bars with sandcoated surfaces over helical wrapping were used. The beam specimens were designed in accordance with Annex S of CSA S806-12 and tested under four-point bending over a clear span of 2700 mm until failure. The beam test results are introduced and discussed in terms of cracking behavior, deflection, and failure modes. The test results yielded an average k b of 0.76, which is in agreement with the CSA S6-14 recommendation of 0.8 for sand-coated bars. Moreover, comparing the results to code provisions showed that CSA S806-12 may yield reasonable yet conservative deflection predictions at service load for the beams reinforced with BFRP bars.

Research paper thumbnail of Distribution expérimentale des contraintes le long d'ancrages scellés dans un massif rocheux soumis à des charges de tenionnement

Research paper thumbnail of Durability of Tokyo Rope carbon cables in alkaline environment

Research paper thumbnail of Physical and mechanical characteristics of new basalt-FRP bars for reinforcing concrete structures

Construction and Building Materials, 2015

h i g h l i g h t s Physical and mechanical characterization of newly developed basalt FRP bars f... more h i g h l i g h t s Physical and mechanical characterization of newly developed basalt FRP bars for concrete members. Durability of BFRP bars in harsh alkaline conditions simulating the concrete environment. Discussion of BFRP characterization and durability results and compare them against the requirements of FRP standards.

Research paper thumbnail of Construction, instrumentation et essais d’une dalle de tablier de pont en béton armé de PRFV conçue avec la méthode empirique

La dégradation des dalles de tabliers en béton est un problème très répandu dans les ponts du Can... more La dégradation des dalles de tabliers en béton est un problème très répandu dans les ponts du Canada et dans le monde entier. Cette dégradation est principalement causée par la corrosion des armatures d’acier dans le béton. Cette corrosion est accélérée par l’application de sel de déglaçage durant les mois d’hiver ou par un environnement agressif. Les armatures en polymères renforcés de fibres (PRF) constituent une solution afin de contrer la dégradation prématurée et coûteuse de ces structures. De nombreuses études et recherches ont été réalisées avec ce type de matériau au cours des dernières années. De plus, des armatures de PRF ont été utilisées dans la construction de plusieurs ponts routiers au Québec, au Canada et aux États-Unis. Dans le cas des dalles de tablier sur poutre, le Code canadien sur le calcul des ponts routiers (CAN/CSA S6) permet l’utilisation de la méthode empirique pour la conception de dalles armées de PRF. Toutefois, depuis son adoption dans l’édition de 200...

Research paper thumbnail of Degradation Assessment of Internal Continuous Fiber Reinforcement in Concrete Environment

The Fiber Reinforced Polymer properties include high strength-to-weight ratio, high stiffness-to-... more The Fiber Reinforced Polymer properties include high strength-to-weight ratio, high stiffness-to-weight ratio, high-energy absorption, and outstanding corrosion and fatigue damage resistance. Therefore, the use of continuous basalt, glass, and carbon fiber reinforcement in concrete structural applications seems to be promising for reinforcing new concrete structures and strengthening applications. The main objective of this study was to evaluate the characteristics of glass fiber reinforced polymer (GFRP) bars, basalt fiber reinforced polymer (BFRP) reinforcing and prestressing bars, and carbon fiber composite prestressing cables. The test variables included the tensile strength, the modulus of elasticity, behavior, and durability under severe environmental exposures. The study investigated the physical and mechanical properties, durability, and bond strength to concrete of the FRP composites. In addition, the investigators tested concrete beams and slabs reinforced with basalt (BFR...

Research paper thumbnail of Evaluation of Shear Behavior for One-Way Concrete Slabs Reinforced with Carbon-FRP Bars

: Nine one-way concrete slabs reinforced with carbon-FRP bars were constructed and tested to fail... more : Nine one-way concrete slabs reinforced with carbon-FRP bars were constructed and tested to failure under two-point loading. The effect of reinforcement ratios, bar diameters, and various concrete compressive strengths were investigated to determine the concrete’s contribution to shear strength. Slab structural behavior in terms of crack patterns, modes of failure, and ultimate capacities were examined. All slabs ultimately failed in shear that caused rupture and complete separation of both parts of the slab. One of the tested slabs, however, formed more main shear-crack branches, yielding progressive post-peak failure, which protected it from experiencing the catastrophic explosive mode of failure as did the other slabs. The results are compared to the concrete-contribution models derived from CSA S806-12, , CSA S6.1S1-06 ACI 440.1R-06, and JSCE97.

Research paper thumbnail of Behaviour of Shear Critical FRP Reinforced Concrete One-Way Slabs

Bridge deck and parking garage slabs are exposed to aggressive environments particularly in the N... more Bridge deck and parking garage slabs are exposed to aggressive environments particularly in the North American regions resulting from the excessive use of de-icing salts. Fiber-reinforced-polymer (FRP) reinforcements have emerged as a practical and sustainable anti-corrosive reinforcing material with superior tensile strength to overcome the corrosion problem. High comfort level and increase use of the material is currently seen. Protection and regulations policies of some Public North American agencies currently include GFRP reinforcing bars as premium reinforcement. Shear behaviour in RC slabs is examined since most of the bridge deck and parking garage slabs are shear-critical. However, there is still no agreement in FRP design codes and guidelines for shear strength equations. Several design code equations are still based on empirical relationships while recent developments are based on shear theories. The complex nature of shear phenomena which is influenced by many parameters,...

Research paper thumbnail of Pullout behaviour of GFRP bars with anchor head in geopolymer concrete

Composite Structures, 2015

The geopolymer concrete internally reinforced with fibre-reinforced polymer (FRP) bars is anticip... more The geopolymer concrete internally reinforced with fibre-reinforced polymer (FRP) bars is anticipated to offer durable, sustainable, and cost-effective civil infrastructures. In this study, the effect of the anchor head on the pullout behaviour of the sand coated glass-fibrereinforced polymer (GFRP) bars embedded in the geopolymer concrete was investigated using a direct pullout test. Straight and headed GFRP bars with different nominal diameters Ø (12.7 mm, 15.9 mm, and 19.0 mm) and embedment lengths l d (0Ø+l ah , 5Ø+l ah , and 10Ø+l ah for headed bars, where l ah stands for the anchor head length, and 5Ø and 10Ø for straight bars) were considered. The results showed that the provision of anchor head is an efficient method to enhance the anchorage capacity of GFRP bars in geopolymer concrete. The anchor heads improved the anchorage of the sand coated GFRP bars by as much as 49% to 77%. Furthermore, the mechanical bearing resistance provided by the anchor head alone resulted in the development of approximately 45% of the GFRP bars' nominal tensile strength. A comparison of the experimental results with the published studies showed that a much higher load is required to pullout the GFRP bars in geopolymer concrete than in Ordinary Portland Cement-based concrete.

Research paper thumbnail of Reinforcement of concrete using fibre-reinforced polymer composites

Durability of Composites for Civil Structural Applications, 2007

... internal reinforcements. Studies by Vijay and Gangarao (1999) indicated that reinforcing bars... more ... internal reinforcements. Studies by Vijay and Gangarao (1999) indicated that reinforcing bars with urethane-modified biphenol vinylester exhibited the lowest vulnerability to different harsh environments. Among unsaturated ...

Research paper thumbnail of Tests Methods to Determine Properties of FRP Rods for Concrete Structures

Composites in Construction, 2001

Research paper thumbnail of PDF (2807 K) - NRC Research Press

Research paper thumbnail of Bond Strength of FRP Rebar Splices

Research paper thumbnail of Caractéristiques mécaniques et élastiques de bétons à haute performance confectionnés avec différents types de gros granulats

Materials and Structures, 1994

Résumé Dans cette étude, on a mis en évidence le rôle que jouent les gros granulats sur les prop... more Résumé Dans cette étude, on a mis en évidence le rôle que jouent les gros granulats sur les propriétés mécaniques et élastiques d'un béton à haute performance. Quatre types de roches, desquelles ont été extraits les gros granulats, ont été sélectionnés. Deux rapports eau/liant de 0,27 et 0,22 ont été utilisés pour la détermination des mélanges des bétons à haute performance.

Research paper thumbnail of Laboratory evaluation of cement-based grouts and grouted rock anchors

International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts, 1995

The paper reports the findings of a laboratory study on six different types of cement-based grout... more The paper reports the findings of a laboratory study on six different types of cement-based grouts and two types of steel rock anchors. The physical and mechanical characteristics of cement grouts employing silica fume, aluminium powder, superplasticizer or sand are compared with those of conventional cement grouts. Pullout tests of grouted, 7-strand steel cable and solid steel threadbar were conducted under similar conditions for different grouts and embedment lengths. From the results obtained, an empirical equation is derived for the estimation of anchor pullout resistance for a given embedment length. A simple trilinear constitutive model for shear bond stress-slip relation at the anchor-grout interface is proposed and discussed.

Research paper thumbnail of Seismic flexural behavior of concrete connections reinforced with CFRP bars and grids

Composite Structures, 2011

ABSTRACT The corrosion of steel reinforcement in concrete and the resulting deterioration of stru... more ABSTRACT The corrosion of steel reinforcement in concrete and the resulting deterioration of structures prompted research on fiber reinforced polymers (FRP) as potential reinforcement for concrete members, for use in new construction. FRPs have more favorable advantages for new concrete buildings subjected to seismic loads particularly in corrosive environment.A comprehensive experimental research program was conducted at Ottawa University in Canada to investigate the behavior of FRP reinforced concrete joints to develop design and detailing requirements for FRP reinforced concrete joints under seismic loading. Three large-scale FRP reinforced concrete structural joints were designed, constructed, and tested under cyclic loading. The specimens were T-shape joints consisting of two columns and one beam representing half portion of the first and the second floor of one-bay reinforced concrete frame, or exterior joint of frames with more than one bay. The columns were subjected to the constant axial load and the beams were under reversed cyclic loading. The reinforcement cage was consisted of CFRP bars as longitudinal reinforcement and CFRP grids as transverse reinforcement. The paper presents the details and results of the experimental programs. The results indicate that FRP reinforcement can be used effectively in new concrete buildings. Photographs taken at the selected stages of loading illustrated the performance of each joint. The hysteretic behavior was presented in terms of force–displacement and moment–drift relationships and other hysteretic relationships. Spacing of CFRP grids and arrangement of longitudinal CFRP bars were the main test parameters.

Research paper thumbnail of Scaling of strength of FRP reinforced concrete beams without shear reinforcement

Among the unresolved issues in the design of structural concrete reinforced with fiber reinforced... more Among the unresolved issues in the design of structural concrete reinforced with fiber reinforced composite (FRP) bars, the understanding of size effect in the reduction of the shear strength of deep beams without shear reinforcement is of fundamental and practical sig- nificance. Size effect accrues primarily from the larger width of diagonal cracks as the effective depth is increased, and has been extensively documented in the case of steel reinforced concrete (RC) through a number of laboratory tests. In FRP RC, the lower longitudinal elastic modulus of the flexural reinforcement results in deeper and wider cracks. Yet, the calibration of any of the current semi-empirical design algorithms is based on test results of beams and one-way slabs with maximum effective depth of 360 mm, which is not representative of relevant large-scale applications. This paper presents and discusses the results of laboratory testing of large-size and scaled FRP RC beams without shear reinforcement, having maximum effective depth of 147, 294 and 883 mm, and effective reinforcement ratio of 0.12% and 0.24%. It is shown that the shear strength of the large-size specimens with less flexural reinforcement decreases on average by 55% compared with the smaller specimens. However, the conservativeness of the current de- sign algorithms generally offsets the size effect. The provisions of the UK Institution of Struc- tural Engineers (ISE) and the Italian National Research Council (CNR) provide the most accu- rate estimates, where the former yields more conservative and consistent results.

Research paper thumbnail of BASALT FRP REINFORCING BARS FOR CONCRETE STRUCTURES

The increasing use of fiber-reinforced polymer (FRP) bars encourages utilizing new fiber types, s... more The increasing use of fiber-reinforced polymer (FRP) bars encourages utilizing new fiber types, such as basalt fibers, rather than the commonly used fibers (glass, aramid, and carbon). However, extensive investigations are needed to evaluate the short-and long-term characteristics of these newly developed bars. This investigation aims at characterizing newly developed basalt fiber-reinforced polymer (BFRP) bars and tendons. The investigation included physical and mechanical characterizations of two different products of deformed BFRP bars (type A and type B) of 8 mm-diameter and one product of BFRP tendons of 7 mm diameter (for prestressing purposes). The test results confirmed that the developed BFRP bars meet the physical and mechanical properties requirements of CSA S807-10.