Frederic Michel - Academia.edu (original) (raw)

Papers by Frederic Michel

Research paper thumbnail of Effect of Crushing Method on the Properties of Produced Recycled Concrete Aggregates

Buildings

Construction and Demolition Waste (C&DW) is generated around the world and its quantity will incr... more Construction and Demolition Waste (C&DW) is generated around the world and its quantity will increase in the future. Recycling has become the favored method of dealing with concrete waste but, to avoid its downcycling, it is important to develop a recycling process which is able to produce high-grade recycled concrete aggregates (RCA). To that end, studying the influence of the production process on the properties of RCA can prove to be a crucial step toward a more circular construction industry. In this study, the influence of the crushing method is investigated. Samples of five laboratory-made concretes have been crushed using the most common mechanical crushing methods (impact crusher and jaw crusher), and the particle size distribution, morphology, hardened cement paste content and water absorption of the produced RCA have been measured and analyzed. The findings indicate that the use of impact crushers results in the production of RCA possessing more spherical geometric charact...

Research paper thumbnail of Influence of Activators on Mechanical Properties of Modified Fly Ash Based Geopolymer Mortars

Materials, 2020

The aim of this work was to study the influence of the type of activator on the formulation of mo... more The aim of this work was to study the influence of the type of activator on the formulation of modified fly ash based geopolymer mortars. Geopolymer and alkali-activated materials (AAM) were made from fly ashes derived from coal and biomass combustion in thermal power plants. Basic activators (NaOH, CaO, and Na2SiO3) were mixed with fly ashes in order to develop binding properties other than those resulting from the use of Portland cement. The results showed that the mortars with 5 mol/dm3 of NaOH and 100 g of Na2SiO3 (N5-S22) gave a greater compressive strength than other mixes. The compressive strengths of analyzed fly ash mortars with activators N5-S22 and N5-C10 (5 mol/dm3 NaOH and 10% CaO) varied from 14.3 MPa to 5.9 MPa. The better properties of alkali-activated mortars with regular fly ash were influenced by a larger amount of amorphous silica and alumina phases. Scanning electron microscopy and calorimetry analysis provided a better understanding of the observed mechanisms.

Research paper thumbnail of Use of Recycled Fine Aggregates from C&DW for Unbound Road Sub-Base

Materials, 2020

Fine recycled aggregates are produced in large quantities when crushing Construction and Demoliti... more Fine recycled aggregates are produced in large quantities when crushing Construction and Demolition Waste (C&DW). Even if coarse recycled aggregates are commonly used for road foundations, fine particles are often rejected as they are considered detrimental for the long-term behaviour of foundations. Physicochemical, mineralogical and mechanical characterizations (through X-ray diffraction, X-ray fluorescence, the chloride and sulphate contents, Los Angeles abrasion, micro-Deval resistance and static plate load tests) were performed on raw and treated fine recycled materials for understanding both the effects of the preparation, the compaction and the freeze–thaw cycles on the properties and the evolution of fine particles. Special attention was provided to the shape analysis of fines by means of image analyser. The results showed that the main characteristic parameters to be considered are the sieving curve and the proportion of grades. The mixes containing the highest quantity of ...

Research paper thumbnail of Influence de la fraction granulaire et de l'origine des granulats recyclés sur leurs propriétés

De très grandes quantités de déchets de construction et de démolition sont produites chaque année... more De très grandes quantités de déchets de construction et de démolition sont produites chaque année. Afin de faire bon usage des granulats recyclés (GR) dans le béton, il est très important d'étudier l'influence de la fraction granulaire et de l'origine des granulats recyclés sur leurs propriétés. Dans cette étude, les granulats recyclés de blocs (GR_Blocs) et de hourdis (GR_Hourdis) ont été concassés et puis séparés en 4 fractions granulaires (0/2, 2/6,3, 6,3/14, 14/20mm). Chaque fraction granulaire des GR a été caractérisée. Les résultats montrent que la teneur en pâte de ciment durcie des GR augmente lorsque la taille des particules diminue. Les sables recyclés possèdent ainsi des teneurs en pâte de ciment nettement plus élevées que les gravillons recyclés. Les sables recyclés possèdent en particulier un coefficient d'absorption d'eau très élevé par rapport aux gravillons recyclés. Les valeurs de teneur en pâte de ciment durcie obtenues pour les GR_Blocs sont pl...

Research paper thumbnail of SCC 2007 Ghent Influence of Physico-Chemical Characteristics of Limestone Fillers on Fresh and Hardened Mortar Performances

ID Number (given by the scientific editors/organizers): 206

Research paper thumbnail of Intra granular porosity of mineral powders: modeling and experimentation

Materials and Structures, 2021

Recycled concrete aggregate (RCA) possess high water absorption, due to the porosity of the attac... more Recycled concrete aggregate (RCA) possess high water absorption, due to the porosity of the attached hardened cement paste they contain. Fine particles of RCA are composed of larger amounts of hardened cement paste, which makes their valorization even more difficult in concrete or mortar. One way to valorize these fine particles could be to use them as mineral addition, however their water absorption coefficient has to be determined, which is tricky for powders. The objective of this work is to estimate the remaining intra granular porosity of a ground powder using two different original approaches. The first modelling approach considers that the porous monolith material is composed of series of pores with characteristic volumes. A pore is considered opened due to grinding if it is cut by the surface of the particle and if its size is larger than the smallest inter granular pore. The remaining porosity after grinding is computed from the pore size distribution of the monolith material and the particle size distribution of the powder. The second experimental approach is based on mercury intrusion porosimetry tests performed on the powder. The separation between inter and intra granular porosity allows the estimation of the powder's remaining porosity. The obtained results show a good agreement between the two approaches in the case of disconnected pores. However, in the case of connected porosity, the experimental approach over estimates the amount of inter-granular porosity.

Research paper thumbnail of Use of grinded hardened cement pastes as mineral addition for mortars

Journal of Building Engineering, 2021

This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Research paper thumbnail of Hygro-thermal and durability properties of a lightweight mortar made with foamed plastic waste aggregates

Construction and Building Materials, 2018

h i g h l i g h t s Foamed end-of-waste plastic aggregates were used instead of natural silica sa... more h i g h l i g h t s Foamed end-of-waste plastic aggregates were used instead of natural silica sand. Increasing artificial aggregates content an increase of macropores was observed. Water vapour permeability increased while capillary water absorption decreased. Plastic aggregates reduced both mortar density and thermal conductivity. Lightweight mortars are suitable as pavement and/or roofing materials.

Research paper thumbnail of Data on thermal conductivity, water vapour permeability and water absorption of a cementitious mortar containing end-of-waste plastic aggregates

Data in brief, 2018

The data presented in this article are related to the research article entitled "Hygro-therm... more The data presented in this article are related to the research article entitled "Hygro-thermal and durability properties of a lightweight mortar made with foamed plastic waste aggregates" (Coppola et al., 2018) [1]. This article focuses the attention on thermal conductivity, water vapour permeability and water absorption of a lightweight cementitious mortar containing foamed end-of-waste plastic aggregates, produced via foam extrusion process [2]. Thermal conductivity, water vapour permeability and water absorption data are made available to allow comparison and/or extend the analysis. Experimental investigations showed that the presence of plastic aggregates decreased thermal conductivity, water vapour resistance and capillary water absorption.

Research paper thumbnail of Improving the properties of recycled concrete aggregates by accelerated carbonation

Proceedings of the Institution of Civil Engineers - Construction Materials, 2017

Large amounts of construction and demolition wastes, especially concrete wastes, are generated an... more Large amounts of construction and demolition wastes, especially concrete wastes, are generated annually. Until now, only a small fraction of concrete wastes has been reused as recycled concrete aggregates (RCA) in the manufacture of mortar and concrete. In order to optimise the use of RCA for new concrete, it is important to improve the properties of RCA. RCA are mainly composed of an intimate mix of natural aggregates and adherent hardened cement paste, which has a much larger porosity than natural aggregates. The influence of accelerated carbonation on the properties of RCA was studied in this work. Original concrete was manufactured and crushed by a jaw crusher in the laboratory. The different fractions of laboratory-produced RCA were stored in an accelerated carbonation room. The mass loss, density, porosity and water absorption of the RCA were tested before and after carbonation. Industrial RCA were also studied for comparison with the laboratory-produced RCA. The results clear...

Research paper thumbnail of Shape Analysis of Fine Aggregates Used for Concrete

Image Analysis & Stereology, 2016

Fine aggregate is one of the essential components in concrete and significantly influences the ma... more Fine aggregate is one of the essential components in concrete and significantly influences the material properties. As parts of natures, physical characteristics of fine aggregate are highly relevant to its behaviors in concrete. The most of previous studies are mainly focused on the physical properties of coarse aggregate due to the equipment limitations. In this paper, two typical fine aggregates, i.e. river sand and crushed rock, are selected for shape characterization. The new developed digital image analysis systems are employed as the main approaches for the purpose. Some other technical methods, e.g. sieve test, laser diffraction method are also used for the comparable references. Shape characteristics of fine aggregates with different origins but in similar size ranges are revealed by this study. Compared with coarse aggregate, fine grains of different origins generally have similar shape differences. These differences are more significant in surface texture properties, whic...

Research paper thumbnail of Experimental study of the drying kinetics for mortar

Research paper thumbnail of Characterization of Fine Aggregate in Concrete by Differente Experimental Approaches

Research paper thumbnail of Surfology Based Concrete Repair Engineering

Research projects performed at the University of Liege and the Warsaw University of Technology ha... 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.

Research paper thumbnail of Transport properties of nano-clay modified hydrophobic concrete

In this work the performance of a traditional concrete modified by the addition of nanoparticles ... more In this work the performance of a traditional concrete modified by the addition of nanoparticles and of a hydrophobic resin were studied. In particular, water capillary suction, water absorption at atmospheric pressure and under vacuum, chloride diffusion, sulphates resistance and carbonation rate tests were carried out. The nanocomposite concrete (hydrophobic and not hydrophobic) shows efficacy in inhibiting the water absorption and CO2 transport thanks to the internal microstructure modification induced by the nanoparticles action which makes more difficult the passage of the substances. Hydrophobic concrete, instead, very effectively avoids the water inlet, but, because of its hydrophobic character, makes the pores of concrete unsatured of water and the CO2 can diffuse faster through the concrete bulk.Peer reviewe

Research paper thumbnail of Use of contaminated recycled aggregates for concrete design: properties and durability

Construction waste management is a quite important economic and environmental deal for our societ... more Construction waste management is a quite important economic and environmental deal for our societies. More than 2 million tons demolition and construction wastes are annually produced only in Wallonia, Southern Region of Belgium; recycling has clearly to be promoted. Roller Compacted Concrete (RCC) is a special dry concrete made of aggregates, water and low quantity of cement, laid down and compacted like a soil, for the construction of massive structures like dams or large horizontal surfaces like road foundations. Replacement of natural aggregates by concrete road recycled aggregates in the mix design of concrete is a solution to decrease nature depletion. Natural concrete slabs were cured in water, sea water, chloride solutions or sulphate solutions and then crushed to obtain virgin and contaminated (polluted) recycled aggregates. The aim of this research is the total replacement (100% coarse and fine) of natural aggregates (NA) by recycled concrete aggregates (RA) in the composition of a roller compacted concrete. The natural and recycled aggregates are characterised and compared. The mechanical properties and durability performances of concrete with contaminated RA are analysed. The experimental results showed that the polluted RA are much richer in chlorides than in sulphates and are leached if they are soaked in water. Significant differences were observed between the properties of original and new concrete and the results demonstrated the need of taking these contaminations into account.

Research paper thumbnail of Durabilité des ciments ternaires à base de laitier vis-à-vis des attaques sulfatiques

Research paper thumbnail of Some effects of limestone fillers as a partial substitute for cement in mortar composition

Limestone filler is a raw material that is already used in several applications like paints, bric... more Limestone filler is a raw material that is already used in several applications like paints, bricks, bituminous mixes, … Moreover, and particularly in Belgium, classical additions like fly ashes and blast furnace slags become rare. There is a need for new additions that could have a positive effect on the properties of the fresh and hardened cementitous composites. Substitution of limestone filler in Portland cement and blast furnace slag cement has been realized between 15 and 27 % in mass. In addition to the characterization of the powder itself-specific mass, specific surface and laser granulometry-the problem of the water demand has been analysed: it seems that it remains constant with the substitution rate. Electric conductivity has also been performed in order to study the evolution of the "dormant" period. Tests on hardened mortars concerned the mechanical properties, the evolution of the porosity and the durability. The i factor indicates a higher value and the porosity seems to be better in the case of blast furnace slags cements, partially due to a very low diameter of the slags particles. Oxygen permeability doesn't seem to be influenced by the filler while capillary absorption increases with substitution rate. Finally, carbonation rate, sulphate resistance and chloride penetration show quite interesting behaviours, leading to the conclusion that this material needs more investigations in order to define optimum application conditions in cementitous matrixes.

Research paper thumbnail of Use of concrete recycled aggregates in roller compacted concrete

ID Number: 336 Author contacts Authors E-Mail Fax Postal address Pascal DELHEZ Pascal.delhez@stud... more ID Number: 336 Author contacts Authors E-Mail Fax Postal address Pascal DELHEZ Pascal.delhez@student.ulg.ac.be 32.4.366.93.65 Civil and Mechanical Engineering Institute Chemin des Chevreuils, 1 (B52/3) B 4000 LIEGE (BELGIUM) Xavier WILLEM Xavier.Willem@ulg.ac.be 32.4.366.93.65 idem Frederic MICHEL Frederic.Michel@ulg.ac.be 32.4.366.93.65 idem Luc COURARD Luc.Courard@ulg.ac.be 32.4.366.93.65 idem Contact person for the paper: Luc COURARD Presenter of the paper during the Conference: Xavier WILLEM 3 Total number of pages of the paper (this one excluded): 9

Research paper thumbnail of Surfology: concrete surface evaluation prior to repair

WIT Transactions on Engineering Sciences, 2009

The study of adhesion of repair materials on concrete structures implies a good knowledge of the ... more The study of adhesion of repair materials on concrete structures implies a good knowledge of the influence of concrete surface treatment. The effects of surface preparation technique are rarely clearly described and parameterised: it is consequently difficult to point out the real influence of roughness on adhesion results. A large research project has been realized with regards to the influence of concrete substrate strength and preparation technique efficiency. The surface roughness of concrete has been quantified by means of the projection "Moiré" technique, which is an interferometrical measurement method. Comparison between polished, scrabbled and hydro-jetted surfaces evaluation is presented.

Research paper thumbnail of Effect of Crushing Method on the Properties of Produced Recycled Concrete Aggregates

Buildings

Construction and Demolition Waste (C&DW) is generated around the world and its quantity will incr... more Construction and Demolition Waste (C&DW) is generated around the world and its quantity will increase in the future. Recycling has become the favored method of dealing with concrete waste but, to avoid its downcycling, it is important to develop a recycling process which is able to produce high-grade recycled concrete aggregates (RCA). To that end, studying the influence of the production process on the properties of RCA can prove to be a crucial step toward a more circular construction industry. In this study, the influence of the crushing method is investigated. Samples of five laboratory-made concretes have been crushed using the most common mechanical crushing methods (impact crusher and jaw crusher), and the particle size distribution, morphology, hardened cement paste content and water absorption of the produced RCA have been measured and analyzed. The findings indicate that the use of impact crushers results in the production of RCA possessing more spherical geometric charact...

Research paper thumbnail of Influence of Activators on Mechanical Properties of Modified Fly Ash Based Geopolymer Mortars

Materials, 2020

The aim of this work was to study the influence of the type of activator on the formulation of mo... more The aim of this work was to study the influence of the type of activator on the formulation of modified fly ash based geopolymer mortars. Geopolymer and alkali-activated materials (AAM) were made from fly ashes derived from coal and biomass combustion in thermal power plants. Basic activators (NaOH, CaO, and Na2SiO3) were mixed with fly ashes in order to develop binding properties other than those resulting from the use of Portland cement. The results showed that the mortars with 5 mol/dm3 of NaOH and 100 g of Na2SiO3 (N5-S22) gave a greater compressive strength than other mixes. The compressive strengths of analyzed fly ash mortars with activators N5-S22 and N5-C10 (5 mol/dm3 NaOH and 10% CaO) varied from 14.3 MPa to 5.9 MPa. The better properties of alkali-activated mortars with regular fly ash were influenced by a larger amount of amorphous silica and alumina phases. Scanning electron microscopy and calorimetry analysis provided a better understanding of the observed mechanisms.

Research paper thumbnail of Use of Recycled Fine Aggregates from C&DW for Unbound Road Sub-Base

Materials, 2020

Fine recycled aggregates are produced in large quantities when crushing Construction and Demoliti... more Fine recycled aggregates are produced in large quantities when crushing Construction and Demolition Waste (C&DW). Even if coarse recycled aggregates are commonly used for road foundations, fine particles are often rejected as they are considered detrimental for the long-term behaviour of foundations. Physicochemical, mineralogical and mechanical characterizations (through X-ray diffraction, X-ray fluorescence, the chloride and sulphate contents, Los Angeles abrasion, micro-Deval resistance and static plate load tests) were performed on raw and treated fine recycled materials for understanding both the effects of the preparation, the compaction and the freeze–thaw cycles on the properties and the evolution of fine particles. Special attention was provided to the shape analysis of fines by means of image analyser. The results showed that the main characteristic parameters to be considered are the sieving curve and the proportion of grades. The mixes containing the highest quantity of ...

Research paper thumbnail of Influence de la fraction granulaire et de l'origine des granulats recyclés sur leurs propriétés

De très grandes quantités de déchets de construction et de démolition sont produites chaque année... more De très grandes quantités de déchets de construction et de démolition sont produites chaque année. Afin de faire bon usage des granulats recyclés (GR) dans le béton, il est très important d'étudier l'influence de la fraction granulaire et de l'origine des granulats recyclés sur leurs propriétés. Dans cette étude, les granulats recyclés de blocs (GR_Blocs) et de hourdis (GR_Hourdis) ont été concassés et puis séparés en 4 fractions granulaires (0/2, 2/6,3, 6,3/14, 14/20mm). Chaque fraction granulaire des GR a été caractérisée. Les résultats montrent que la teneur en pâte de ciment durcie des GR augmente lorsque la taille des particules diminue. Les sables recyclés possèdent ainsi des teneurs en pâte de ciment nettement plus élevées que les gravillons recyclés. Les sables recyclés possèdent en particulier un coefficient d'absorption d'eau très élevé par rapport aux gravillons recyclés. Les valeurs de teneur en pâte de ciment durcie obtenues pour les GR_Blocs sont pl...

Research paper thumbnail of SCC 2007 Ghent Influence of Physico-Chemical Characteristics of Limestone Fillers on Fresh and Hardened Mortar Performances

ID Number (given by the scientific editors/organizers): 206

Research paper thumbnail of Intra granular porosity of mineral powders: modeling and experimentation

Materials and Structures, 2021

Recycled concrete aggregate (RCA) possess high water absorption, due to the porosity of the attac... more Recycled concrete aggregate (RCA) possess high water absorption, due to the porosity of the attached hardened cement paste they contain. Fine particles of RCA are composed of larger amounts of hardened cement paste, which makes their valorization even more difficult in concrete or mortar. One way to valorize these fine particles could be to use them as mineral addition, however their water absorption coefficient has to be determined, which is tricky for powders. The objective of this work is to estimate the remaining intra granular porosity of a ground powder using two different original approaches. The first modelling approach considers that the porous monolith material is composed of series of pores with characteristic volumes. A pore is considered opened due to grinding if it is cut by the surface of the particle and if its size is larger than the smallest inter granular pore. The remaining porosity after grinding is computed from the pore size distribution of the monolith material and the particle size distribution of the powder. The second experimental approach is based on mercury intrusion porosimetry tests performed on the powder. The separation between inter and intra granular porosity allows the estimation of the powder's remaining porosity. The obtained results show a good agreement between the two approaches in the case of disconnected pores. However, in the case of connected porosity, the experimental approach over estimates the amount of inter-granular porosity.

Research paper thumbnail of Use of grinded hardened cement pastes as mineral addition for mortars

Journal of Building Engineering, 2021

This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Research paper thumbnail of Hygro-thermal and durability properties of a lightweight mortar made with foamed plastic waste aggregates

Construction and Building Materials, 2018

h i g h l i g h t s Foamed end-of-waste plastic aggregates were used instead of natural silica sa... more h i g h l i g h t s Foamed end-of-waste plastic aggregates were used instead of natural silica sand. Increasing artificial aggregates content an increase of macropores was observed. Water vapour permeability increased while capillary water absorption decreased. Plastic aggregates reduced both mortar density and thermal conductivity. Lightweight mortars are suitable as pavement and/or roofing materials.

Research paper thumbnail of Data on thermal conductivity, water vapour permeability and water absorption of a cementitious mortar containing end-of-waste plastic aggregates

Data in brief, 2018

The data presented in this article are related to the research article entitled "Hygro-therm... more The data presented in this article are related to the research article entitled "Hygro-thermal and durability properties of a lightweight mortar made with foamed plastic waste aggregates" (Coppola et al., 2018) [1]. This article focuses the attention on thermal conductivity, water vapour permeability and water absorption of a lightweight cementitious mortar containing foamed end-of-waste plastic aggregates, produced via foam extrusion process [2]. Thermal conductivity, water vapour permeability and water absorption data are made available to allow comparison and/or extend the analysis. Experimental investigations showed that the presence of plastic aggregates decreased thermal conductivity, water vapour resistance and capillary water absorption.

Research paper thumbnail of Improving the properties of recycled concrete aggregates by accelerated carbonation

Proceedings of the Institution of Civil Engineers - Construction Materials, 2017

Large amounts of construction and demolition wastes, especially concrete wastes, are generated an... more Large amounts of construction and demolition wastes, especially concrete wastes, are generated annually. Until now, only a small fraction of concrete wastes has been reused as recycled concrete aggregates (RCA) in the manufacture of mortar and concrete. In order to optimise the use of RCA for new concrete, it is important to improve the properties of RCA. RCA are mainly composed of an intimate mix of natural aggregates and adherent hardened cement paste, which has a much larger porosity than natural aggregates. The influence of accelerated carbonation on the properties of RCA was studied in this work. Original concrete was manufactured and crushed by a jaw crusher in the laboratory. The different fractions of laboratory-produced RCA were stored in an accelerated carbonation room. The mass loss, density, porosity and water absorption of the RCA were tested before and after carbonation. Industrial RCA were also studied for comparison with the laboratory-produced RCA. The results clear...

Research paper thumbnail of Shape Analysis of Fine Aggregates Used for Concrete

Image Analysis & Stereology, 2016

Fine aggregate is one of the essential components in concrete and significantly influences the ma... more Fine aggregate is one of the essential components in concrete and significantly influences the material properties. As parts of natures, physical characteristics of fine aggregate are highly relevant to its behaviors in concrete. The most of previous studies are mainly focused on the physical properties of coarse aggregate due to the equipment limitations. In this paper, two typical fine aggregates, i.e. river sand and crushed rock, are selected for shape characterization. The new developed digital image analysis systems are employed as the main approaches for the purpose. Some other technical methods, e.g. sieve test, laser diffraction method are also used for the comparable references. Shape characteristics of fine aggregates with different origins but in similar size ranges are revealed by this study. Compared with coarse aggregate, fine grains of different origins generally have similar shape differences. These differences are more significant in surface texture properties, whic...

Research paper thumbnail of Experimental study of the drying kinetics for mortar

Research paper thumbnail of Characterization of Fine Aggregate in Concrete by Differente Experimental Approaches

Research paper thumbnail of Surfology Based Concrete Repair Engineering

Research projects performed at the University of Liege and the Warsaw University of Technology ha... 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.

Research paper thumbnail of Transport properties of nano-clay modified hydrophobic concrete

In this work the performance of a traditional concrete modified by the addition of nanoparticles ... more In this work the performance of a traditional concrete modified by the addition of nanoparticles and of a hydrophobic resin were studied. In particular, water capillary suction, water absorption at atmospheric pressure and under vacuum, chloride diffusion, sulphates resistance and carbonation rate tests were carried out. The nanocomposite concrete (hydrophobic and not hydrophobic) shows efficacy in inhibiting the water absorption and CO2 transport thanks to the internal microstructure modification induced by the nanoparticles action which makes more difficult the passage of the substances. Hydrophobic concrete, instead, very effectively avoids the water inlet, but, because of its hydrophobic character, makes the pores of concrete unsatured of water and the CO2 can diffuse faster through the concrete bulk.Peer reviewe

Research paper thumbnail of Use of contaminated recycled aggregates for concrete design: properties and durability

Construction waste management is a quite important economic and environmental deal for our societ... more Construction waste management is a quite important economic and environmental deal for our societies. More than 2 million tons demolition and construction wastes are annually produced only in Wallonia, Southern Region of Belgium; recycling has clearly to be promoted. Roller Compacted Concrete (RCC) is a special dry concrete made of aggregates, water and low quantity of cement, laid down and compacted like a soil, for the construction of massive structures like dams or large horizontal surfaces like road foundations. Replacement of natural aggregates by concrete road recycled aggregates in the mix design of concrete is a solution to decrease nature depletion. Natural concrete slabs were cured in water, sea water, chloride solutions or sulphate solutions and then crushed to obtain virgin and contaminated (polluted) recycled aggregates. The aim of this research is the total replacement (100% coarse and fine) of natural aggregates (NA) by recycled concrete aggregates (RA) in the composition of a roller compacted concrete. The natural and recycled aggregates are characterised and compared. The mechanical properties and durability performances of concrete with contaminated RA are analysed. The experimental results showed that the polluted RA are much richer in chlorides than in sulphates and are leached if they are soaked in water. Significant differences were observed between the properties of original and new concrete and the results demonstrated the need of taking these contaminations into account.

Research paper thumbnail of Durabilité des ciments ternaires à base de laitier vis-à-vis des attaques sulfatiques

Research paper thumbnail of Some effects of limestone fillers as a partial substitute for cement in mortar composition

Limestone filler is a raw material that is already used in several applications like paints, bric... more Limestone filler is a raw material that is already used in several applications like paints, bricks, bituminous mixes, … Moreover, and particularly in Belgium, classical additions like fly ashes and blast furnace slags become rare. There is a need for new additions that could have a positive effect on the properties of the fresh and hardened cementitous composites. Substitution of limestone filler in Portland cement and blast furnace slag cement has been realized between 15 and 27 % in mass. In addition to the characterization of the powder itself-specific mass, specific surface and laser granulometry-the problem of the water demand has been analysed: it seems that it remains constant with the substitution rate. Electric conductivity has also been performed in order to study the evolution of the "dormant" period. Tests on hardened mortars concerned the mechanical properties, the evolution of the porosity and the durability. The i factor indicates a higher value and the porosity seems to be better in the case of blast furnace slags cements, partially due to a very low diameter of the slags particles. Oxygen permeability doesn't seem to be influenced by the filler while capillary absorption increases with substitution rate. Finally, carbonation rate, sulphate resistance and chloride penetration show quite interesting behaviours, leading to the conclusion that this material needs more investigations in order to define optimum application conditions in cementitous matrixes.

Research paper thumbnail of Use of concrete recycled aggregates in roller compacted concrete

ID Number: 336 Author contacts Authors E-Mail Fax Postal address Pascal DELHEZ Pascal.delhez@stud... more ID Number: 336 Author contacts Authors E-Mail Fax Postal address Pascal DELHEZ Pascal.delhez@student.ulg.ac.be 32.4.366.93.65 Civil and Mechanical Engineering Institute Chemin des Chevreuils, 1 (B52/3) B 4000 LIEGE (BELGIUM) Xavier WILLEM Xavier.Willem@ulg.ac.be 32.4.366.93.65 idem Frederic MICHEL Frederic.Michel@ulg.ac.be 32.4.366.93.65 idem Luc COURARD Luc.Courard@ulg.ac.be 32.4.366.93.65 idem Contact person for the paper: Luc COURARD Presenter of the paper during the Conference: Xavier WILLEM 3 Total number of pages of the paper (this one excluded): 9

Research paper thumbnail of Surfology: concrete surface evaluation prior to repair

WIT Transactions on Engineering Sciences, 2009

The study of adhesion of repair materials on concrete structures implies a good knowledge of the ... more The study of adhesion of repair materials on concrete structures implies a good knowledge of the influence of concrete surface treatment. The effects of surface preparation technique are rarely clearly described and parameterised: it is consequently difficult to point out the real influence of roughness on adhesion results. A large research project has been realized with regards to the influence of concrete substrate strength and preparation technique efficiency. The surface roughness of concrete has been quantified by means of the projection "Moiré" technique, which is an interferometrical measurement method. Comparison between polished, scrabbled and hydro-jetted surfaces evaluation is presented.