References of "Michel, Frédéric"
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See detailInternal sulfate attack in mortars containing contaminated fine recycled concrete aggregates
Colman, Charlotte ULiege; Bulteel, David; Thiery, Vincent et al

in Construction and Building Materials (in press)

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See detailInfluence of hydrophobic product nature and concentration on carbonation resistance of cultural heritage concrete buildings
Courard, Luc ULiege; Zhao, Zengfeng ULiege; Michel, Frédéric ULiege

in Cement and Concrete Composites (2020), 115

The concrete based patrimony is subjected to different deterioration mechanisms, including steel corrosion induced by carbonation or chloride ion diffusion. Hydrophobic product may be used for protecting ... [more ▼]

The concrete based patrimony is subjected to different deterioration mechanisms, including steel corrosion induced by carbonation or chloride ion diffusion. Hydrophobic product may be used for protecting concrete structures against water ingress. No data are available on the correlation between quality of hydrophobic agent, concrete substrate properties and carbonation resistance. The influence of hydrophobic product and water to cement ratio of concrete substrate on the carbonation resistance has been investigated. The results show that there is a clear effect of hydrophobic treatment on carbonation resistance as well as chloride diffusion, specifically for high active product concentration and high W/C ratio. [less ▲]

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See detailUse of municipal solid waste incineration bottom ash for roller compacted concrete
Zhao, Zengfeng ULiege; HYOUMBI TCHUNGOUELIEU, William; Michel, Frédéric ULiege et al

Scientific conference (2020, September)

241 million tons of municipal solid waste (MSW) is generated annually in the European Union (data from 2014), which produce 16 million tons of MSW incineration bottom ash (MSWIBA) per annum. Due to the ... [more ▼]

241 million tons of municipal solid waste (MSW) is generated annually in the European Union (data from 2014), which produce 16 million tons of MSW incineration bottom ash (MSWIBA) per annum. Due to the promotion of waste recycling, the use of MSWIBA as construction materials has gained much attention during the last decade. In this paper, the use of MSWIBA as aggregate for roller compacted concrete has been assessed. [less ▲]

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See detailUse of Recycled Fine Aggregates from C&DW for Unbound Road Sub-Base
Courard, Luc ULiege; Rondeux, Mélanie ULiege; Zhao, Zengfeng ULiege et al

in Materials (2020), 13(13), 2994

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 ... [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 fine particles, specifically lower than 63 µm, usually inducing a higher water demand and a higher capillary rise. This can be explained by specific surface and bluntness parameters which increase with the finer particles, inducing a higher surface roughness and, consequently, a higher potential interaction with water. Compaction did not seem to have a major effect on the production of fines (despite some breakdown occurred during compaction) and on the shape of materials (the bluntness and convexity increased slightly, while the elongation values remained similar after the compaction process). The static plate load tests showed that bearing capacity is slightly lower than the specifications for the road foundation after compaction. However, the studied material could meet the maximum criteria for secondary roads foundation construction on the wear resistance criteria. Recycled aggregates from C&DW without sufficient quality could be blended with other aggregates to enable their usage for upper-level road foundation. [less ▲]

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See detailInfluence of Activators on Mechanical Properties of Modified Fly Ash Based Geopolymer Mortars
Prochon, Piotr ULiege; Zhao, Zengfeng ULiege; Courard, Luc ULiege et al

in Materials (2020), 13(5),

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 ... [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. [less ▲]

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See detailUse of grinded hardened cement pastes as mineral addition in mortars
Bouarroudj, Mohamed Elkarim ULiege; Remond, Sébastien; Bulteel, David et al

in Journal of Building Engineering (2020), 101863

Recycled Concrete Aggregates (RCA) are not enough used in the construction sector due to their high porosity and water absorption capacity. Fine particles which are composed of large amounts of attached ... [more ▼]

Recycled Concrete Aggregates (RCA) are not enough used in the construction sector due to their high porosity and water absorption capacity. Fine particles which are composed of large amounts of attached hardened cement paste are even more difficult to valorize, while they could be used as mineral admixture in mortar or concrete. The objective of this work is to find a recovery track for this material as mineral addition. The use of a porous powder as mineral admixture in cementitious mortars raises the question of the effective water definition in such systems. Two powders are used, the first one is a grinded hardened cement paste (porous), and the second one is a limestone filler (non-porous). A comparison of the hydration degree, porosity, fresh, and hardened behaviors between cement pastes and mortars manufactured with the two powders is carried out. The results show that the porosity of the grinded hardened cement paste has an impact on the properties of cementitious materials. Depending on the studied properties (fresh or hardened properties), the substitution of cement by the porous powder could be done with, or without taking into account the water absorption. Taking into account the water absorption allows maintaining the fluidity of the mixture but decreases significantly the compressive strength for cement replacement percentages larger than 20%. [less ▲]

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See detailConstruction and Demolition Wastes: specific conditions for recycling in North West Europe
Delvoie, Simon ULiege; Courard, Luc ULiege; Hubert, Julien ULiege et al

in Cement, Wapno, Beton (2020), 1

The Construction and Demolition Wastes (C&DW) are estimated at one third of total wastes generated in the European Union and represent the main flux in volume. Inert materials (e.g. concrete, bricks ... [more ▼]

The Construction and Demolition Wastes (C&DW) are estimated at one third of total wastes generated in the European Union and represent the main flux in volume. Inert materials (e.g. concrete, bricks, tiles and ceramics) constitute the largest fraction of construction and demolition wastes. These wastes can be recovered as secondary raw materials after a recycling process resulting in the production of recycled sands and aggregates. The market for recycled sands and aggregates is however complex and sensitive. It can be affected by many parameters and may be very variable from one region to another, even in the same country. A quantitative analysis of market is carried out in five North West European countries: Belgium, France, Germany, Luxembourg and the Netherlands. For achieving this analysis, attention is paid to the following data/parameters: generation of inert construction and demolition wastes, production of recycled sands and aggregates and production of natural sands and aggregates. Since the market of recycled products is also governed by transportation costs (mainly transported by road), the study has also compiled data on the density of recycling plants for construction and demolition wastes, the density of pits and quarries extracting natural materials, the density of inert landfills and taxes applied for C&DW landfilling. National/regional legislation and requirements are also included in the analysis. Based on the compiled data and objective reasons, it is observed that the market of recycled sands and aggregates is more developed and more suitable in the Netherlands and in Flanders (North of Belgium) than is the other investigated countries/regions. [less ▲]

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See detailRECYCLING FINE PARTICLES FROM CONSTRUCTION AND DEMOLITION WASTES: CHARACTERIZATION AND EFFECTS ON CONCRETE PERFORMANCES
Courard, Luc ULiege; Bouarroudj, El Karim Mohamed ULiege; Colman, Charlotte ULiege et al

in International Journal of Minerals, Metallurgy and Materials (2020)

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See detailDetermination of sorption isotherm of mortar and modeling of water diffusivity
Kahlerras, Loubna ULiege; Belhamri, Azeddine; Fraikin, Laurent ULiege et al

Poster (2019, July 11)

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See detailMarket analysis of recycled sands and aggregates in North-West Europe: drivers and barriers
Delvoie, Simon ULiege; Zhao, Zengfeng ULiege; Michel, Frédéric ULiege et al

in Conference Series Earth and Environmental Science (2019, February)

Construction and demolition wastes (C&DW) are estimated at one third of total wastes generated in the European Union (EU) and represent the main flux in volume. Inert materials (e.g. concrete, bricks ... [more ▼]

Construction and demolition wastes (C&DW) are estimated at one third of total wastes generated in the European Union (EU) and represent the main flux in volume. Inert materials (e.g. concrete, bricks, tiles and ceramics) constitute the largest fraction of construction and demolition wastes. These wastes can be recovered as secondary raw materials after a recycling process resulting in the production of recycled sands and aggregates. The market for recycled sands and aggregates is however complex and sensitive. It can be affected by many parameters and may be very variable from one region to another, even in the same country. A quantitative analysis of some market variables is carried out in five NW European countries: Belgium, France, Germany, Luxembourg and the Netherlands. For achieving this analysis, attention is paid to the following data/parameters: generation of inert construction and demolition wastes, production of recycled sands and aggregates and production of natural sands and aggregates. Since the market of recycled products is also governed by transportation costs (mainly transported by road), the study has also compiled data on the density of recycling plants for construction and demolition wastes, the density of pits and quarries extracting natural materials, the density of inert landfills and taxes applied for C&DW landfilling. National/regional legislation and requirements are also included in the analysis. Based on the compiled data and objective reasons, the market of recycled sands and aggregates is more developed and more suitable in the Netherlands and in Flanders (North of Belgium) than in the other investigated countries/regions. [less ▲]

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See detailCO2 CAPTURE FOR MINERALIZED MISCANTHUS AGGREGATES
Grigoletto, Sophie ULiege; Courard, Luc ULiege; Zhao, Zengfeng ULiege et al

in CO2 Storage in Concrete (2019)

At a time when the cement industry is largely responsible for the production of CO2 in the construction sector, it is useful to make this production a reverse phenomenon: that’s CO2 capture. The CO2 ... [more ▼]

At a time when the cement industry is largely responsible for the production of CO2 in the construction sector, it is useful to make this production a reverse phenomenon: that’s CO2 capture. The CO2 absorption process called carbonation, improves specific properties of the concrete during the conversion of carbon dioxide CO2 into calcium carbonate CaCO3. Current environmental concerns motivate the study of carbonation in order to maximize the absorption of carbon dioxide. Experimentation has been performed on bio-based and recycled concrete aggregates. The long term stability as well as the reinforcement of bio-based aggregates – miscanthus - may be obtained by means of a mineralization process of the natural product: a preparation with a lime and/or cement-based material is necessary to reinforce the cohesion of the bio-based product. Specific conditions for CO2 capture have been tested and concrete blocks have been produced with aggregates. Performances of aggregates and concrete blocks before and after carbonation are presented and show increasing performances in specific situations of CO2 capture. [less ▲]

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See detailUse of a reference limestone fine aggregate to study the fresh and hard behavior of mortar made with recycled fine aggregate
Bouarroudj, M. E. K.; Remond, Sébastien; Michel, Frédéric ULiege et al

in Materials and Structures (2019), 52(18),

Recycled fine concrete aggregates (RFA) are not enough used in the construction sector, mainly because of their high water absorption capacity. These fine particles are composed of crushed natural ... [more ▼]

Recycled fine concrete aggregates (RFA) are not enough used in the construction sector, mainly because of their high water absorption capacity. These fine particles are composed of crushed natural aggregate and adherent hardened cement paste. The main goal of this research is to compare the behaviors of mortars made either with RFA or with a model limestone fine natural aggregate (LFA). The LFA is prepared in order to obtain physical properties as close as possible to those of the RFA. A specific characterisation is carried out to compare the density, water absorption, morphology of grains, size distribution and packing density of both aggregates. Mortars are then manufactured with same composition and same volume of LFA and RFA. Different states of moisture of the RFA are studied. The fresh behaviour of the mortar made with saturated RFA is very close to that of the mortar made with LFA which confirms that the latter is a good reference compared to the RFA. Comparison of fresh behaviours of mortars made with RFA of different state of moisture to that of mortar made with saturated sand allows then to determine the water absorbed in the different moisture conditions. Afterwards, a mechanical study is realised, taking into consideration the exact quantity of absorbed water of the RFA in dry or saturated conditions. Knowing the exact effective water value allows us to study both the strength of mortar made with RFA, the strength of the matrix and the adherence between the fine aggregate and the paste. © 2019, RILEM. [less ▲]

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See detailOptimizing performances of recycled aggregates for improving concrete properties
Courard, Luc ULiege; Tabarelli, Enrico ULiege; Michel, Frédéric ULiege et al

in Proceedings SMSS 2019 (2019)

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 ... [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 and by products to be valorised as secondary raw materials. The influence of the fine recycled concrete aggregates (FRCA) on the mechanical and durability properties of concrete was used for producing concrete. Concretes with different substitution rates (0, 30 and 100%) of natural sand by the FRCA were manufactured. Mechanical properties (compressive strength) and durability properties (capillary absorption, carbonation depth, and freeze/thaw resistance) were investigated. The results show that the compressive strength of concrete decreased as the substitution of FRCA increased. Durability of concrete could be strongly influenced by the high porosity and water absorption of fine recycled concrete aggregates. Brick fillers (BF) have also been studied for producing Self Compacting Mortars (SCM): introduction of 50 and 100% substitution clearly show a reduction of workability properties if particles water absorption is not taken into account. However, mechanical properties at 7 and 28 days didn’t show a clear impact of the substitution of limestone filler by brick filler. [less ▲]

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See detailInfluence of alkali activator on fly ash based geopolymer formation
Prochon, Piotr ULiege; Zhao, Zengfeng ULiege; Piotrowski, Tomasz et al

Scientific conference (2018, November 08)

The aim of this work is to study the influence of the type of activator on the formulation of geopolymers based on fly ash. Geopolymers were made from fly ash from thermal power plants and biomass. Basic ... [more ▼]

The aim of this work is to study the influence of the type of activator on the formulation of geopolymers based on fly ash. Geopolymers were made from fly ash from thermal power plants and biomass. Basic activators (NaOH, quicklime, sodium silicate) were added as well as silicates in order to develop binding properties other than those resulting from the use of cement. The results showed that the basic activators based on 5 mol/L of NaOH and 22% of sodium silicate (N5-S22) gave a greater compressive strength. The compressive strengths of the regular fly ash mortar with activators N5-S22 and N5-C10 (5 mol/L NaOH and 10% quicklime) are respectively 14.3 MPa and 10.8 MPa while with biomass fly ash and activators N5-S22 and N5-C10, the compressive strength of geopolymers reached 6.8 MPa and 5.9 MPa respectively. The greater properties of geopolymers obtained with regular fly ash are due to the larger amount of amorphous silica and alumina phases. Scanning electron microscopy and calorimetry analysis provided a better understanding of the observed mechanisms. [less ▲]

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See detailState of the art on recycling techniques for the production of recycled sands and aggregates from construction and demolition wastes
Delvoie, Simon ULiege; Zhao, Zengfeng ULiege; Michel, Frédéric ULiege et al

in Nguyen, T.T.; Waldmann, D.; Venditti, S. (Eds.) Circular Concrete - SeRaMCo - Secondary Raw Materials for Concrete Precast Products (2018, November)

Construction and demolition wastes (C&DW) are estimated at one third of total wastes generated in the European Union (EU) and represent the main flux in volume. These wastes can be recycled in suitable ... [more ▼]

Construction and demolition wastes (C&DW) are estimated at one third of total wastes generated in the European Union (EU) and represent the main flux in volume. These wastes can be recycled in suitable recycling facilities which include a series of techniques able to crush and sort materials to finally produce recycled sands and aggregates with required properties. Common sorting techniques consist in ferrous metal sorting, hand-picking sorting and washing or air shifting sorting. Crushing is usually carried out by an impact or a jaw crusher and less frequently by a cone crusher. A combination of different crushers is also common for stationary recycling plants. In order to continuously improve the quality of the produced recycled materials, results obtained from innovative recycling techniques are also increasingly documented in literature. Some of the main innovative techniques related to C&DW recycling purposes are introduced in the study. [less ▲]

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See detailUtilisation des sables et granulats recyclés dans le béton préfabriqué : comparaison des exigences réglementaires et techniques en Europe
Delvoie, Simon ULiege; Zhao, Zengfeng ULiege; Michel, Frédéric ULiege et al

Conference (2018, November)

L’utilisation des sables et granulats recyclés dans le béton préfabriqué est encore peu fréquente sur le plan industriel, et ce malgré les nombreuses recherches menées sur ce sujet. Dans un premier temps ... [more ▼]

L’utilisation des sables et granulats recyclés dans le béton préfabriqué est encore peu fréquente sur le plan industriel, et ce malgré les nombreuses recherches menées sur ce sujet. Dans un premier temps, cette étude fait le point sur les législations et les réglementations prises par les différents pays du nord-ouest de l’Europe (Allemagne, Belgique, France, Luxembourg et Pays-Bas) en vue de favoriser le recyclage et la valorisation des sables et granulats recyclés issus des déchets de construction et de démolition. Ces pays disposent d’un cadre législatif et réglementaire développé leur permettant d’atteindre l’objectif fixé par la Directive européenne 2008/98/CE visant à recycler et valoriser au moins 70% des déchets non dangereux de construction et de démolition en 2020. Le cadre normatif, en lien avec la production de béton préfabriqué et l’utilisation de sables et granulats recyclés, est ensuite analysé. Les principales normes européennes concernées sont : EN 206:2013+A1:2016 (béton), EN 13369:2018 (produits préfabriqués en béton) et EN 12620:2013 (granulats pour béton). Ces normes ont été, selon les cas, complétées ou non par des annexes nationales. Une attention est portée à la comparaison des différentes normes entre les pays du nord-ouest de l’Europe. Cette analyse comparative se penche (i) sur les taux de substitution maximum définis par la norme EN 206:2013+A1:2016 et les annexes nationales, ainsi que (ii) sur les caractéristiques que doivent avoir les granulats recyclés pour pouvoir être incorporés dans le béton. Les normes belge et française semblent plus restrictives vis-à-vis du taux de substitution maximum par rapport aux autres normes étudiées, tandis que les normes belge et luxembourgeoise semblent plus contraignantes concernant les caractéristiques que doivent avoir les granulats recyclés pour pouvoir être utilisés dans le béton. [less ▲]

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See detailGypsum residues in recycled materials: characterization of fine recycled aggregates
Colman, Charlotte ULiege; Zhao, Zengfeng ULiege; Michel, Frédéric ULiege et al

Scientific conference (2018, August 26)

Globally, half of all generated waste is produced by the building sector. The finer fraction of this construction and demolition waste (C&DW) is often polluted with substances harmful for the durability ... [more ▼]

Globally, half of all generated waste is produced by the building sector. The finer fraction of this construction and demolition waste (C&DW) is often polluted with substances harmful for the durability of concrete, which is why their incorporation into a new structure is generally avoided. The most important contamination present in these materials consists of gypsum (CaSO4.2H2O) residues from the construction or demolition site. The presence of sulfates from this gypsum may complicate and accelerate the sulfate attack reaction, which is a deteriorating process that causes the expansive formation of the mineral ettringite. The high volume of this ettringite will cause an expansive stress within the concrete, with degradation and cracking of the structure as a result. Additionally, the leaching of sulfates can give rise to environmental problems. In this project, the fine fraction of C&DW from different industrial sources was investigated, to establish the gypsum contamination of actual recycled materials. Ion chromatography was used to determine the concentration of water soluble sulfates. Results showed a variable sulfate content, depending heavily on the source of the materials. Nevertheless, the total amounts surpassed the acceptable sulfate contents specified in the European standard EN 206. The obtained information about the concentration and size distribution of sulfate contamination in fine recycled materials (FRA) will help the development of a testing protocol for the effects of internal sulfate attack caused by gypsum residues. [less ▲]

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See detailEffects of limestone filler on the behaviour of recycled aggregate concrete
Zhao, Zengfeng ULiege; Courard, Luc ULiege; Michel, Frédéric ULiege et al

Scientific conference (2018, August 26)

According to the concept of sustainable development, sustainable construction is becoming a hot topic. Large amounts of construction and demolition wastes, especially concrete wastes, are generated ... [more ▼]

According to the concept of sustainable development, sustainable construction is becoming a hot topic. Large amounts of construction and demolition wastes, especially concrete wastes, are generated annually. Meanwhile, large quantities of natural aggregates are needed for the construction of roads, buildings or civil engineering infrastructures. Until now, only a small part of concrete wastes is re-used as recycled concrete aggregates (RCA) in the manufacture of mortar and concrete. The issue of recycling construction and demolition wastes in the concrete industry has been widely explored by many researchers. RCA are mainly composed of an intimate mix between natural aggregates and adherent hardened cement paste or mortar. The later possesses a large water demand which makes it harder to recycle into concrete than natural aggregates. Limestone powder, which is a by-product of calcareous aggregate production, if not used, has to be disposed of in the landfills at a considerable cost. In this paper, the effect of limestone filler on the properties of recycled aggregate concrete (RAC) was studied. Recycled aggregates were produced in the laboratory from the crushing of concrete blocks and were then used as aggregates into new concretes. Concretes were manufactured by adding different percentages of limestone filler (0%, 10% and 20% of the mass of cement) and by replacing 30% of natural aggregate with recycled aggregates. Then, fresh properties and mechanical properties of these concretes were investigated. The results showed that the compressive strength of concrete with the addition of 10% limestone was 47.2 MPa after 28 days, which was larger than the reference concrete (43.1 MPa). [less ▲]

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See detailFeasible use of construction and demolition waste in concrete production: SeRaMCo project
Zhao, Zengfeng ULiege; Delvoie, Simon ULiege; Michel, Frédéric ULiege et al

Conference (2018, August 09)

About 850 million tons of construction and demolition waste (C&DW) are produced yearly in European Union. The Waste Framework Directive 2008/98/EC aims to a minimum target of reuse, recycling, and ... [more ▼]

About 850 million tons of construction and demolition waste (C&DW) are produced yearly in European Union. The Waste Framework Directive 2008/98/EC aims to a minimum target of reuse, recycling, and material recovery of non-hazardous C&DW at 70% by weight until 2020. Recycling of C&DW is quite important and has to be promoted. Up to now, most of recycled C&DW has been used as a base and sub-base materials in road construction, while only a small quantity of C&DW is reused in concrete. Interreg North-Western Europe project SeRaMCo (Secondary Raw Materials for Concrete Precast Products) aims to replace primary raw materials with the high-quality materials recycled from C&DW, e.g. concrete, bricks, tiles and ceramics (CBTC), in production of the cement and concrete products for use in North-Western Europe. To attain this goal, the project will: a) analyse and improve sorting of C&DW; b) develop and test new concrete mixes and technologies for the production of concrete precast products (CPPs) made from the recycled CBTC; c) establish a market niche for CPPs, leading to the economic advantages for the producers and generating new jobs in the construction sector. [less ▲]

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See detailInternal sulfate attack caused by gypsum contamination of recycled aggregates: development of a swelling test protocol
Colman, Charlotte ULiege; Zhao, Zengfeng ULiege; Michel, Frédéric ULiege et al

Conference (2018, July 12)

Sulfate attack is a deteriorating process for concrete, where the formation of expansive minerals such as ettringite causes the swelling of a material. The sulfates necessary for this reaction can come ... [more ▼]

Sulfate attack is a deteriorating process for concrete, where the formation of expansive minerals such as ettringite causes the swelling of a material. The sulfates necessary for this reaction can come from an external (such as sea- or groundwater) or an internal (such as cement or aggregates) source. A specific situation within this problematic is the contamination of recycled aggregates with gypsum from the demolition site. To assess the extent of the damage that this gypsum contamination can cause, the length of cementitious mixes that incorporated recycled aggregates needs to be monitored. The challenge in this research exists in finding the right testing protocol to follow the development of sulfate attack. Being a slow reaction which can take several months, accelerating procedures could be necessary. Different methods are described, but do not seem to be applicable in this specific context of gypsum contamination. In this paper, fine recycled aggregates contaminated with different levels of gypsum are subjected to a set of various storage conditions and/or aging cycles. The results show that existing protocols, set up specifically for internal sulfate attack, do not provide the acceleration or aggravation of the reaction as might have been shown before. A definitive testing protocol, to be used in this specific situation, is eventually proposed. [less ▲]

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