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

in Grantham, Michael (Ed.) 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 (Ed.) Proceedings of the 5th International Conference on Concrete Repair (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 detailEffect of misalignment on pull-off 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 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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See detailSurface properties of concrete and criteria for adhesion of repair systems
Courard, Luc ULg; Garbacz, Andrzej; Piotrowski, Tomasz et al

in Van Gemert, Dionys; Kabashi, Naser; Nushi, Violeta (Eds.) et al Proceedings of the 1st Symposium on Polymers in Concrete (2013)

Before any repair operation, an effective assessment of the concrete substrate has to be performed. Usually next to the surface reparation of concrete, evaluation of the cohesion of the superficial ... [more ▼]

Before any repair operation, an effective assessment of the concrete substrate has to be performed. Usually next to the surface reparation of concrete, evaluation of the cohesion of the superficial concrete is requested for adhesion and durability reasons. Many authors describe the influence of the surface preparation technique on the superficial cohesion of concrete or the adhesion. However, the real effects of surface preparation technique only begin to be investigated in terms of superficial microcracking or roughness quantification. This project was performed in regards to the influence of concrete substrate strength and preparation technique efficiency. The effect of the concrete removal/preparation technique is most likely dependent upon the nature and the quality of the concrete substrate. Preparation techniques are compared from the point of view of concrete removing but also potential deterioration. The visual observation of the concrete surfaces indicates that the high pressure water jetting technique induces a particular texture characterized by large waves mostly parallel to the water flow. The concrete slabs have afterwards been covered with a Self-Compacting Repair Mortar and adhesion has been characterized. [less ▲]

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See detailA surface engineering approach applicable to concrete repair engineering
Garbacz, Andrzej; Courard, Luc ULg; Bissonnette, Benoît

in Bulletin of the Polish Academy of Sciences. Technical Sciences (2013), 61(1), 73-84

The objective of the paper is to analyze the effect of surface roughness and superficial microcracking upon dhesion of repair systems using concrete surface engineering approach. The results presented in ... [more ▼]

The objective of the paper is to analyze the effect of surface roughness and superficial microcracking upon dhesion of repair systems using concrete surface engineering approach. The results presented in this paper have been obtained within the framework of research projetcs performed to develop a better understanding of factors affecting the adhesion of repair materials through a surface engineering approach. Based on the results of investigations, the authors showed that the durability and quality of concrete repairs depend to a large degree on the characteristics of the substrate. Mechanical preparation and profiling of the concrete surface to be repaired has to be balanced with potential co-lateral effects such as superficial cracking, too often induced as a result of inappropriate concrete removal method selection, and the loss of benefits due to better mechanical anchorage. The results obtained confirm also that Concrete Surface Engineering, as a scientific concept, will definitely contribute to shed more light on how to optimize repair bond, taking into account interactions between materials at different observation scales. [less ▲]

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See detailTopography evaluation methods for concrete substrates: parametric study
Courard, Luc ULg; Garbacz, Andrzej; Bissonnette, Benoît

in Alexander, Mark (Ed.) Concrete Repair, Rehabilitation and Retrofitting III (2012)

Research projects performed at the University of Liege, Laval University and the Warsaw University of Technology have pointed out the importance of taking care about the surface roughness of concrete ... [more ▼]

Research projects performed at the University of Liege, Laval University and the Warsaw University of Technology have pointed out the importance of taking care about the surface roughness of concrete substrate with regards to the adhesion of repair materials. This paper wants to make a State-of-Art on this specific problem: surfometry methods, interface analysis, adhesion measurements, …etc are presented, interpreted and compared. Surfology, which is a more wide concept, contributes to understand what will make the contact effective or not, and allow interactions of variable intensities between the materials. Different scales of observation – micro to macro - are needed to exactly represent what happens when materials are put into contact. [less ▲]

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See detailSurfology Based Concrete Repair Engineering
Courard, Luc ULg; Michel, Frédéric ULg; Garbacz, Andrzej et al

in Polymers in sustainable construction (2011)

Research projects performed at the University of Liege and the Warsaw University of Technology have pointed out the importance of taking care about surfology of materials: if durability also means ... [more ▼]

Research projects performed at the University of Liege and the Warsaw University of Technology have pointed out the importance of taking care about surfology of materials: if durability also means sustainability, we may then consider that optimization in material selection is essential for repair efficient. Surfology contributes to understand what will make the contact effective or not, and allow interactions of variable intensities between the materials. Different scales of observation – micro to macro - are needed to exactly represent what happens when materials are put into contact. [less ▲]

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See detailConcrete Repair Science: new trends - 10 Years cooperation between the University of Liège and the Politechnika Warsawska
Courard, Luc ULg; Garbacz, Andrzej

Book published by Université de Liège (2010)

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See detailSurfology: new investigations techniques and approaches
Courard, Luc ULg; Garbacz, Andrzej

Scientific conference (2010, November 29)

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See detailRelation between bond quality and impact-echo frequency spectrum
Piotrowski, Tomasz; Garbacz, Andrzej; Van der Wielen, Audrey ULg et al

in Restoration of Buildings and Monuments = Bauinstandsetzen und Baudenkmalpflege (2010), 16(4/5), 303-314

According to EN 1504-10 and ACI Concrete Repair Manual, bond strength and interface quality are the main features of repair system necessary to be assessed. Pull-off test is most commonly used for bond ... [more ▼]

According to EN 1504-10 and ACI Concrete Repair Manual, bond strength and interface quality are the main features of repair system necessary to be assessed. Pull-off test is most commonly used for bond strength evaluation but growing interest in nondestructive techniques (NDT) is recently noted. Impact-echo (IE) is treated as the most promising one for this purpose. The aim of this paper is to analyze an effect of bond quality on stress wave propagation in repair systems. A group of samples has been prepared in order to obtain repair systems of different bond quality. Prior to repair, quality of concrete substrates has been characterized according different techniques: compressive strength, superficial cohesion, surface roughness index and cracking quantification. Than a polymer-modified repair mortar has been applied. After hardening, IE signals have been recorded and pull-off bond strength determined. The relationships between parameters characterizing surface quality, bond strength, IE frequency spectrum and results of wavelet analysis of IE signal have been analyzed. [less ▲]

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See detailOn the relation between bond quality and impact-echo frequency spectrum
Piotrowski, Tomasz; Garbacz, Andrzej; Van der Wielen, Audrey ULg et al

in Proceedings of the 13th International Congress on Polymers in Concrete ICPIC 2010 (2010)

According to EN 1504-10 and ACI Concrete Repair Manual, bond strength and interface quality are the main features of repair system necessary to be assessed. Pull-off test is most commonly used for bond ... [more ▼]

According to EN 1504-10 and ACI Concrete Repair Manual, bond strength and interface quality are the main features of repair system necessary to be assessed. Pull-off test is most commonly used for bond strength evaluation but growing interest in nondestructive techniques (NDT) is recently noted. Impact-echo (IE) is treated as the most promising one for this purpose. The aim of this paper is to analyze an effect of bond quality on stress wave propagation in repair systems. A group of samples has been prepared in order to obtain repair systems of different bond quality. Prior to repair, quality of concrete substrates has been characterized according different techniques: compressive strength, superficial cohesion, surface roughness index and cracking quantification. Than a polymer-modified repair mortar has been applied. Af-ter hardening, IE signals have been recorded and pull-off bond strength determined. The rela-tionships between parameters characterizing surface quality, bond strength, IE frequency spec-trum and results of wavelet analysis of IE signal have been analyzed. [less ▲]

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See detailWykorzystanie impact-echo i radaru do wykrywania defektow ukladu naprawczego nie zawierajacych warstwy powietrza
Garbacz, Andrzej; Harassek, Piotr; Van der Wielen, Audrey ULg et al

in 39th Polish Conference on Non destructive Testing Methods, Szczyrk 26-28 October, Zeszyty Problemowe. Badania nieniszczące (2010)

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See detailSurfology: what does it mean for polymer concrete composites?
Courard, Luc ULg; Garbacz, Andrzej

in Restoration of Buildings and Monuments = Bauinstandsetzen und Baudenkmalpflege (2010), 16(4/5), 1-12

Surfology is a scientific concept including all surface properties of materials and its influence on adhesion. The study of adhesion of polymer concrete composites is on the border - interface - between ... [more ▼]

Surfology is a scientific concept including all surface properties of materials and its influence on adhesion. The study of adhesion of polymer concrete composites is on the border - interface - between materials science and engineering. Interface quality is clearly influenced by surface properties of materials. Quality is uneasy to define but, at the level of interface, it could integrate all what favours the contact between concrete and polymers, like shrinkage, rigidity, surface roughness, wettability, viscosity…etc. Surfology contributes to understand what will make the contact effective or not, and allow interactions of variable intensities between the materials. Different scales of observation – micro to macro - are needed to exactly represent what happens when materials are put into contact. The objective of the paper is to analyse the effect of surface parameters (surfology) on polymer concrete composites. Influence of water content, roughness and type of material will be taken into account as factor influencing wettability and thermodynamic properties of surface. Viscosity and shear level of resinous materials will be considered in the same way. Engineering point of view will be taken into account through adhesion evaluation and correlated to surface material properties. [less ▲]

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See detailSurfology: what does it mean for polymer concrete composites?
Courard, Luc ULg; Garbacz, Andrzej

in Proceedings of the 13th International Congress on Polymers in Concrete ICPIC 2010 (2010)

Surfology is a scientific concept including all surface properties of materials and its influence on adhesion. The study of adhesion of polymer concrete composites is on the border - interface - between ... [more ▼]

Surfology is a scientific concept including all surface properties of materials and its influence on adhesion. The study of adhesion of polymer concrete composites is on the border - interface - between materials science and engineering. Interface quality is clearly influenced by surface properties of materials. Quality is uneasy to define but, at the level of interface, it could integrate all what favours the contact between concrete and polymers, like shrinkage, rigidity, surface roughness, wettability, viscosity…etc. Surfology contributes to understand what will make the contact effective or not, and allow interactions of variable intensities between the materials. Different scales of observation – micro to macro - are needed to exactly represent what happens when materials are put into contact. The objective of the paper is to analyse the effect of surface parameters (surfology) on poly-mer concrete composites. Influence of water content, roughness and type of material will be taken into account as factor influencing wettability and thermodynamic properties of surface. Viscosity and shear level of resinous materials will be considered in the same way. Engineering point of view will be taken into account through adhesion evaluation and correlated to surface material properties. [less ▲]

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See detailThe effect of concrete substrate quality towards evaluation of repair system using impact-echo method
Garbacz, Andrzej; Piotrowski, Tomasz; Kwasniewski, L. et al

in Szczesniak, W. E.; A. Zbiciak, A. (Eds.) Theoretical foundations of civil engineering (2009, September)

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See detailSome theoretical and practical considerations about surface preparation of concrete and adhesion of repair systems.
Courard, Luc ULg; Garbacz, Andrzej; Piotrowski, Tomasz

in Sustercic, Jakob (Ed.) <<<<< (2009, May)

Before any repair operation, an effective assessment of the concrete substrate has to be performed. Usually next to the surface reparation of concrete, evaluation of the cohesion of the superficial ... [more ▼]

Before any repair operation, an effective assessment of the concrete substrate has to be performed. Usually next to the surface reparation of concrete, evaluation of the cohesion of the superficial concrete is requested for adhesion and durability reasons. Many authors describe the influence of the surface preparation technique on the superficial cohesion of concrete or the adhesion. However, the real effects of surface preparation technique only begin to be investigated in terms of superficial microcracking or roughness quantification. This project was performed in regards to the influence of concrete substrate strength and preparation technique efficiency. The effect of the concrete removal/preparation technique is most likely dependent upon the nature and the quality of the concrete substrate. Preparation techniques are compared from the point of view of concrete removing but also potential deterioration. The visual observation of the concrete surfaces indicates that the high pressure water jetting technique induces a particular texture characterized by large waves mostly parallel to the water flow. The concrete slabs have afterwards been covered with a Self-Compacting Repair Mortar and adhesion has been characterized. [less ▲]

Detailed reference viewed: 33 (2 ULg)