References of "Garbacz, Andrzej"
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See detailDevelopment of Specifications and Performance Criteria for Surface Preparation Based on Issues Related to Bond Strength
Bissonnette, Benoît; Courard, Luc ULg; Garbacz, Andrzej et al

Report (2017)

In addition to the development of a satisfactory test procedure and recommendations to improve the overall quality of concrete repair works, the authors of this proposal intend to collaborate with various ... [more ▼]

In addition to the development of a satisfactory test procedure and recommendations to improve the overall quality of concrete repair works, the authors of this proposal intend to collaborate with various representatives from public agencies and from the industry to facilitate technological transfer. Presentations will be made in conferences and workshops in North America and Europe. At the end of the project, the results shall include two MSc theses and at least two papers in major journals, such as Concrete International or ACI Materials Journal. Also, the project should provide the basis towards a standard procedure for the evaluation of superficial cohesion of concrete, in relation with surface preparation and concrete removal techniques. Finally, recommendations and specifications could be incorporated in future versions of the ACI-ICRI Manual of Concrete Repairs as well as in DOT’s specifications. [less ▲]

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See detailAdhérence des réparations en béton: concepts, facteurs d'influence et évaluation
Bissonnette, Benoît; Courard, Luc ULg; Garbacz, Andrzej

Scientific conference (2017, February 20)

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See detailMesure de l'adhérence et principaux paramètres d'influence
Bissonnette, Benoît; Courard, Luc ULg; Garbacz, ANdrzej

Scientific conference (2017, February 20)

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See detailNotions de compatibilité relatives au développement de l'adhérence
Courard, Luc ULg; Garbacz, Andrzej; Bissonnette, Benoît

Scientific conference (2017, February 20)

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See detailSurface characterization methods for quality control of repair
Garbacz, Andrzej; Bissonnette, Benoît; Courard, Luc ULg

Scientific conference (2017, February 20)

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See detailOn the evaluation of interface quality in concrete repair system by means of impact-echo signal analysis
Garbacz, Andrzej; Piotrowski, Tomacz; Courard, Luc ULg et al

in Construction and Building Materials (2017), 134

According to Concrete Repair Manual as well as ACI 562-16 and European EN 1504-10 standards, a bond strength as a measure of adhesion is one the main feature of repair system necessary to be assessed. The ... [more ▼]

According to Concrete Repair Manual as well as ACI 562-16 and European EN 1504-10 standards, a bond strength as a measure of adhesion is one the main feature of repair system necessary to be assessed. The most common laboratory and engineering method for bond strength evaluation is pull-off test. This is however a semi-destructive method that needs a repair in a place of measurement. Recently, the great interest in nondestructive techniques (NDT) development is noted. Impact-Echo (IE) is considered as one of the most promising methods for this purpose. In this paper, the study on the usability the IE test based on frequency spectrum analysis for bond strength evaluation is analyzed. Both Finite Element Method (FEM) simulation and experimental tests were performed in order to obtain potential relations between IE frequency spectrum and parameters characterizing concrete substrate quality that may affect the final bond strength and the real value of pull-off bond strength measured on samples as well. It was concluded that the IE method can be a useful tool for interface quality and bond strength evaluations in concrete repair system. However, more complex signal analysis, e.g. wavelet analysis, should be considered in the future. [less ▲]

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See detailA repair quality control with elastic waves based methods vs. substrate quality
Garbacz, Andrzej; Piotrowski, Tomasz; Courard, Luc ULg et al

in Dehn; Beushausen, Hans (Eds.) Concrete Repair, Rehabilitation and Retrofitting IV (2016)

An adhesion in repair system is one of the most important factors that affect the repair efficiency. The elaboration of reliable nondestructive method for an adhesion mapping is one of the most important ... [more ▼]

An adhesion in repair system is one of the most important factors that affect the repair efficiency. The elaboration of reliable nondestructive method for an adhesion mapping is one of the most important tasks. A majority of NDT methods mentioned in EN 1504-10 and ACI Concrete Repair Manual for assessment of concrete structures are based on propagation of stress waves. However, these investigations are rarely focused on evaluation of bond strength. Repair system is difficult to test with NDT methods because of many factors influencing stress wave propagation. In this paper the effect of a quality of concrete substrate on propagation of stress waves in repair system and their influence on possibility of estimation of the bond strength is discussed. [less ▲]

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See detailFundamental approach for the concept of concrete repair compatibility
Courard, Luc ULg; Bissonnette, Benoît; Garbacz, Andrzej

in Dehn, Frank (Ed.) Concrete Repair, Rehabilitation and Retrofitting IV (2016)

Before being translated in terms of physical, mechanical and chemical of materials, the initial step for evaluating compatibility is interface creation. The thermodynamic properties of the materials as ... [more ▼]

Before being translated in terms of physical, mechanical and chemical of materials, the initial step for evaluating compatibility is interface creation. The thermodynamic properties of the materials as well as transport mechanisms – diffusion, capillary succion – at the interface and roughness of the concrete substrate are acting from the beginning and influencing the durability of the bond strength. A review of the main parameters influencing bond development is presented on the base of the equilibrium of the surface free ener-gies of liquid and solid, applied to the concept of repair mortars, coating and hydrophobic treatments [less ▲]

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See detailA quantitative approach to the concept of concrete repair compatibility
Bissonnette, Benoît; Modjabi-Sangnier, François; Courard, Luc ULg et al

in Dehn, Frank; Beushausen, Hans (Eds.) Concrete Repair, Rehabilitation and Retrofitting IV (2016)

The work reported in this paper is part of a wider research program intended to provide the repair industry with improved fundamental knowledge to implement rational design methods and rules for repairs ... [more ▼]

The work reported in this paper is part of a wider research program intended to provide the repair industry with improved fundamental knowledge to implement rational design methods and rules for repairs. In that regard, there is a strong need to study the fundamental relationships and parameters that underlie the repair compatibility concepts, in particular those relating to dimensional compatibility. In the first part of the paper, classical formulas derived for thick cylindrical specimens were used to analyze the tensile stress buildup in annular restrained shrinkage test specimens, taking into account the restraining conditions the investigated ring test method and the individual concrete properties/phenomena determined experimentally (elastic modulus, creep coefficient, drying shrinkage deformation). By comparing the ring test results with the calculated tensile stresses, the validity and accuracy of the theoretical approach could be appraised. A quantitative approach for the evaluation of the performance of concrete repair in terms of dimensional compatibility was then developed. Derived from the basic strain balance approach (ratio between the total deformability in tension and the drying shrinkage deformation), a parameter referred to as dimensional compatibility index (CI) was introduced in order to analyze the evolution of dimensional compatibility as a function of time for a given concrete mixture, taking into account the actual degree of restraint in the element. Compatibility index evolution curves were calculated for various repair concrete mixtures in order to highlight material behavior relating to composition parameters and temperature. As it requires the evaluation of a limited number of individual properties that are for most readily available (i.e. strength, elastic modulus, shrinkage), the compatibility index expressed in terms of deformation carries a lot of potential as a relatively simple and convenient analytical tool for assessing the cracking sensitivity of concrete repair materials. Overall, it can be stated that a good correlation was found between the ring test results and the tensile stress values calculated based on individual concrete properties / phenomena and that the proposed calculation method lays ground for evaluating quantitatively the dimensional compatibility of repair materials and defining suitable performance criteria. [less ▲]

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See detailSpecifying Concrete Repair Materials
Vaysburd, Alex; Bissonnette, Benoît; Garbacz, Andrzej et al

in Materialy Budowlane (2016), 3(523), 42-45

Specification of materials for concrete repair is a complex task requiring broad knowledge of materials science, engineering and construction practice. In this paper, several issues important for proper ... [more ▼]

Specification of materials for concrete repair is a complex task requiring broad knowledge of materials science, engineering and construction practice. In this paper, several issues important for proper design and implementation of concrete repair are discussed. It is stressed that the specification documentation is not a formality, but rather a critically important engineering step in view of fulfilling the durability and service life requirements. [less ▲]

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See detailSymposium 3R: Reduce, Reuse, Recycle in constructions
Garbacz, Andrzej; Courard, Luc ULg

Book published by Warsaw University of Technology (2016)

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See detailÉvaluation des réparations en béton et identification des principaux facteurs d’influence
Bissonnette, Benoît; Courard, Luc ULg; Garbacz, Andrzej et al

in Courard, Luc; Collin, Frédéric; Cerfontaine, Benjamin (Eds.) RUGC 2016 (2016)

La réparation et le renforcement des structures existantes en béton comptent parmi les plus importants défis auxquels les ingénieurs civils sont confrontés aujourd’hui et qu’ils devront relever dans les ... [more ▼]

La réparation et le renforcement des structures existantes en béton comptent parmi les plus importants défis auxquels les ingénieurs civils sont confrontés aujourd’hui et qu’ils devront relever dans les années à venir. Les préoccupations actuelles concernant le développement durable favorisent la réfection au détriment de la construction neuve et ne peuvent que renforcer cette tendance. Des efforts concertés de la part des scientifiques et ingénieurs sont encore nécessaires afin d’améliorer la conception des réparations en béton et d’en assurer la qualité et la fiabilité attendues. L’un des aspects essentiels de la durabilité des réparations en béton et des revêtements ou traitements de surface est la qualité de l’adhérence entre le matériau de réparation et le béton existant. Le présent article résume les principales conclusions de travaux réalisés en collaboration en vue d’identifier les facteurs influençant l’adhérence des réparations (la rugosité, le degré de saturation et la carbonatation du substrat) et l’évaluation de celle-ci en conditions in situ (type de chargement, alignement de l’appareil). Sur la base des résultats recueillis, des recommandations ont été émises dans un guide du USBR [less ▲]

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See detailConcrete Surface Engineering
Courard, Luc ULg; Bissonnette, Benoît; Garbacz, Andrzej

Book published by CRC Press (2015)

The objective of the book is to provide better basic knowledge about concrete surface properties with regard to repair operations. When Long et al. (2001) were asking “Why assess the properties of near-to ... [more ▼]

The objective of the book is to provide better basic knowledge about concrete surface properties with regard to repair operations. When Long et al. (2001) were asking “Why assess the properties of near-to-surface concrete?,” they were referring to bond development, one of the most important research topics in the field of concrete repairs. Adjoining any material to an existing concrete surface intrinsically involves this interfacial issue. Surface engineering is an area of knowledge addressing all surface-related considerations, notably those pertaining to adhesion. It provides a fundamental understanding of what will make the contact effective or not, allowing for interactions of variable intensity between the materials. A variety of suitable scientific tools is available to characterize properties of layer, quality of substrate and adhesion of overlay to substrate. Many of the basics of surface engineering, which has long developed into a discipline in metallurgy, can in fact apply to the repair and surface treatment of concrete, with the main objective of achieving a desired durability. A fundamental approach is presented in this book and explained in connection with a variety of typical concrete repairs and surface treatments. This book is intended to become a leading-edge resource for practicing engineers, architects, repair specialists as well as researchers looking for: • scientific fundamental knowledge needed to understand how a concrete surface may act on adhesion of a variety of systems; • methods and techniques for analysing concrete surface characteristics; • rational means to evaluate advantages and disadvantages of the various surface preparation techniques; • recommendations to ensure satisfactory adherence of repair materials, coatings or injection products to concrete; • guidelines for selecting well adapted repair material and techniques. The authors’ expertise in the field of repair and maintenance of concrete is recognized internationally. They have been involved for many years in the work of related Rilem and ACI workgroups. This book is in fact the result of more than 15 years of collaborative research. [less ▲]

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See detailEffects of limestone fillers on surface free energy and electrical conductivity of the interstitial solution of cement mixes
Courard, Luc ULg; Michel, Frédéric ULg; Perkowicz, Sylwia et al

in Cement and Concrete Composites (2014), 45

Most of concrete formulations actually contain mineral additives that are used as an inert filler or supplementary cementitious material (as type II addition). These materials are generally used in order ... [more ▼]

Most of concrete formulations actually contain mineral additives that are used as an inert filler or supplementary cementitious material (as type II addition). These materials are generally used in order to increase concrete performances both in its fresh and hardened states. The mineral additives usually improve the consistency and workability of fresh concrete and reduce the water demand for a required concrete slump because of an additional volume of fines. The way of action depends on the physical and chemical characteristics of fillers. The study of surface free energies and electric conductivities of interstitial solutions of cement mixes modified by blast furnace slags and limestone fillers contributes to a better knowledge of hardening and interaction process. [less ▲]

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See detailEffect of misalignment on pulloff test results: numerical and experimental assessments
Courard, Luc ULg; Bissonnette, Benoît; Garbacz, Andrzej et al

in ACI Materials Journal (2014), 111(2), 153-162

The successful application of a concrete repair system is often evaluated through pull-off testing. For such in-situ quality control (QC) testing, the inherent risk of misalignment might affect the ... [more ▼]

The successful application of a concrete repair system is often evaluated through pull-off testing. For such in-situ quality control (QC) testing, the inherent risk of misalignment might affect the recorded value and eventually make a difference in the acceptance of the work. So far, the issue of eccentricity in pull-off testing has been ignored in field practice, because it is seen as an academic issue. This paper presents the results of a project intended to quantify the effect of misalignment on pull-off tensile strength evaluation and provide a basis for improving QC specifications if necessary. The test program consisted first in an analytical evaluation of the problem through 2-D FEM simulations and, in a second phase, in laboratory experiments in which the test variables were the misalignment angle (0°, 2° and 4°) and the coring depth (15 mm [1.18 in.], 30 mm [2.36 in.]). It was found that calculations provide a conservative but realistic lower bound limit for evaluation the influence of misalignment upon pull-off test results: a 2° misalignment can be expect to yield a pull-off strength reduction of 7 to 9 % respectively for 15-mm [1.18-in.] and 30-mm [2.36-in.] coring depths, and the corresponding decrease resulting from a 4° misalignment reach between 13 and 16%; From a practical standpoint, the results generated in this study indicate that when specifying a pull-off strength limit in the field, the value should be increased (probable order of magnitude: 15%) to take into account the potential reduction due to testing misalignment. [less ▲]

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See detailConcrete repair bond: evaluation and factors of influence
Bissonnette, Benoît; Courard, Luc ULg; Garbacz, Andrzej et al

in Grantham, Michael; Basheer, Muhammed; Magee, Bryan (Eds.) et al Proceedings of the 5th International Conference on Concrete Repair (2014)

Repair and strengthening of existing concrete structures are among the biggest challenges civil engineers are facing today and will have to face in the years to come. Present concerns of sustainable ... [more ▼]

Repair and strengthening of existing concrete structures are among the biggest challenges civil engineers are facing today and will have to face in the years to come. Present concerns of sustainable development emphasizing repair instead of new construction will only strengthen this trend. Concerted efforts towards improving the durability of concrete repairs are still needed from scientists and engineers. One of the critical aspects of durability of concrete repairs and overlays is lasting and sufficient interfacial bond between repair material and existing concrete substrate. This paper summarizes some of the findings of a collaborative study devoted to the most significant factors influencing bond in repairs (roughness, degree of saturation and carbonation of the substrate) and its field evaluation (type of loading, device misalignment). Based on the test results collected in different test programs, guideline-type recommendations for surface preparation prior to repair were issued. [less ▲]

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See detailEvaluation of the mechanical integrity of a concrete surface by means of combined destructive methods
Courard, Luc ULg; Bissonnette, Benoît; Garbacz, Andrzej et al

in Grantham, Michael; Basheer, Muhammed; Magee, Bryan (Eds.) et al Proceedings of Concrete Solutions (2014)

As a tight bond between the repair and the old concrete is required, the soundness of the prepared surface has to be carefully assessed. This paper presents the results of an investigation intended to ... [more ▼]

As a tight bond between the repair and the old concrete is required, the soundness of the prepared surface has to be carefully assessed. This paper presents the results of an investigation intended to assess and compare quantitatively different test methods, namely the Schmidt rebound hammer, the pull-out test and the pull-off test, to evaluate superficial mechanical integrity of a substrate after concrete removal operations. Although it does not yield a precise evaluation of compressive strength, the Schmidt rebound hammer test is recognized as a useful tool for performing quick surveys to assess concrete uniformity. The pull-off test is very well correlated with the splitting-tensile test, but it is not suited for vertical and overhead surfaces. The Capo pull-out test has limited interest for surface preparation, as it is applicable to flat surfaces only. Conversely, the accelerated pull-out test showed interesting potential as a simple and relatively rapid means for assessing the mechanical integrity of a concrete surface prior to repair for any type of concrete surface. It appears from the results generated in this study that the combination Schmidt hammer / pull-off test could fill the needs for the evaluation of horizontal surfaces after concrete removal, while the combination Schmidt hammer / accelerated pull-out test could be used effectively on vertical and overhead surfaces. [less ▲]

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See detailAdhérence des réparations en béton: évaluation et facteurs d'influence
Bissonnette, Benoït; Courard, Luc ULg; Jolin, Marc et al

in Damidot, Denis (Ed.) Actes de la 15ème édition des journées scientifiques (2014)

La réparation et le renforcement des structures existantes en béton comptent parmi les plus importants défis auxquels les ingénieurs civils sont confrontés aujourd’hui et qu’ils devront relever dans les ... [more ▼]

La réparation et le renforcement des structures existantes en béton comptent parmi les plus importants défis auxquels les ingénieurs civils sont confrontés aujourd’hui et qu’ils devront relever dans les années à venir. Les préoccupations actuelles concernant le développement durable favorisent la réfection au détriment de la construction neuve et ne peuvent que renforcer cette tendance. Des efforts concertés de la part des scientifiques et ingénieurs sont encore nécessaires afin d’améliorer la conception des réparations en béton et d’en assurer la qualité et la fiabilité attendues. L’un des aspects essentiels de la durabilité des réparations en béton et des revêtements ou traitements de surface est la qualité de l’adhérence entre le matériau de réparation et le béton existant. Le présent article résume les principales conclusions de travaux réalisés en collaboration en vue d’identifier les facteurs influençant l’adhérence des réparations (la rugosité, le degré de saturation et la carbonatation du substrat) et l’évaluation de celle-ci en conditions in situ (type de chargement, alignement de l’appareil). Sur la base des résultats recueillis, des recommandations concernant la préparation de la surface avant réparation ont été émises dans un guide du USBR aux États-Unis. [less ▲]

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See detailPatch repair: compatibility issues
Garbacz, Andrzej; Courard, Luc ULg; Bissonnette, Benoît et al

in Grantham, Michael; Basheer, Muhammed; Magee, Bryan (Eds.) et al Proceedings of the 5th International Conference on Concrete Repair (2014)

Repair of any concrete structure results in formation of complex, at least two-component repair systems. Compatibility approach is treated as a basic requirement during selection of repair material ... [more ▼]

Repair of any concrete structure results in formation of complex, at least two-component repair systems. Compatibility approach is treated as a basic requirement during selection of repair material. Recently, the understanding for compatibility requirements in repair systems approach is demonstrated in many papers. The aim of this paper is analyzing the compatibility between repair materials and concrete substrate in the case of patch repair. The compatibility issues were discussed in light of the various requirements which determine the mathematical space of loads, including chemical, mechanical and other physical (mainly thermal) loads. N-dimensional compatibility space is created, taking into account selected patch material control parameters. The requirements for good compatibility between repair material and concrete substrate can be formulated by using mathematical inequalities, where the variables are the material control parameters. The effects of properties of the both repair material and concrete substrate were analyzed using computer system ANCOMP developed at Warsaw University of Technology. Usability of this approach was demonstrated using selected case study as an example. [less ▲]

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See detailNear-to-Surface properties affecting bond strength in concrete repair
Courard, Luc ULg; Piotrowski, Tomasz; Garbacz, Andrzej

in Cement and Concrete Composites (2014), 46

One of the main processes for repairing concrete structures is patch repair. Efficiency and durability of a repaired system depends on the bond between concrete substrate and repair material. By ... [more ▼]

One of the main processes for repairing concrete structures is patch repair. Efficiency and durability of a repaired system depends on the bond between concrete substrate and repair material. By increasing the surface roughness, the surface treatment of concrete substrate can promote mechanical interlocking that is one of the basic mechanisms of adhesion. Nevertheless, some problems may arise from “co-lateral” effects of the treatment, especially due to the development of microcracks inside the substrate. In the presented paper, the effect of concrete substrate surface preparation has been characterized by roughness measurement, description of microcracking in the near-to-surface layer and a pull-off cohesion test. After repair, pull-off bond strength has been evaluated. It is concluded that selection of a suitable surface treatment technique should be preceded by the analysis of its aggressiveness in relation to the concrete substrate strength. A procedure for bond strength estimation using multiple regression approach, based on parameters describing surface quality really generated from various roughening techniques, is then proposed. [less ▲]

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