The Experts below are selected from a list of 41523 Experts worldwide ranked by ideXlab platform
Jean Claude Morel - One of the best experts on this subject based on the ideXlab platform.
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A new methodology to identify and quantify material resource at a large scale for Earth Construction - Application to cob in Brittany
Construction and Building Materials, 2018Co-Authors: Erwan Hamard, Andry Razakamanantsoa, Bogdan Cazacliu, Blandine Lemercier, Jean Claude MorelAbstract:A new methodology based on the cross-referencing of spatialized pedological and heritage data is proposed to identify and quantify soil resources available for Earth Construction. The paper underlines the pedological particularities of areas containing Earth heritage and uses these particularities to propose criteria to assess the suitability of soils for modern Earth Construction. The methodology applied at the regional scale in France (for a given area of 27,200 km2 in Brittany) enabled to specify five new texture classes (balance between clay, silt, sand and gravel content) of suitability for cob soils. This result calls into question recommendations available in the literature. The methodology also provides data on the scale of availability of the resource to repair Earth built heritage (cob) or to build new low impact buildings with integrated modern cob walls. In the studied area the potential waste recovery of 2.8 Mt per year is measured, highlighting the large availability of materials for Earth Construction. At least 23% of Earthwork wastes of Brittany are suitable for Earth Construction (0.7 Mt). However, Earth remains a non-renewable material and this resource has to be properly managed, requiring an appropriate building design and maintenance in order to increase longevity and to avoid the use of admixture, preventing Earth reversibility at end of life.
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Historical rammed Earth process description thanks to micromorphological analysis
International Journal of Architectural Heritage, 2016Co-Authors: Erwan Hamard, Antonin Fabbri, Cécilia Cammas, Andry Razakamanantsoa, Bogdan Cazacliu, Jean Claude MorelAbstract:Rammed Earth was traditionally used in western European countries before industrial building materials replace it during 20th Century. Construction strategies developed by former builders were dictated by locally available Construction materials and engendered local constructive cultures. Unfortunately, this knowledge was orally transmitted and is lost today. The rediscovery of these cultures can provide answers to modern rammed Earth Construction processes. Micromorphological analysis of Earth walls provides information to rediscover traditional rammed Earth process. This methodology is applied for the first time, on a rammed Earth wall of a farm located in Bresse (France). Thanks to this methodology, pedological horizon, extraction depth and location of the material source are identified. The surface area excavated for the Construction of the building is estimated. Micromorphological study gives information on mixing degree and water content at implementation time. Strain features associated with ramming effect and rammed Earth boundary layer are also highlighted. Running Head: Rammed Earth micromorphological analysis
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Cob, a vernacular Earth Construction process in the context of modern sustainable building
Building and Environment, 2016Co-Authors: Erwan Hamard, Andry Razakamanantsoa, Bogdan Cazacliu, Jean Claude MorelAbstract:The will of reducing environmental and social impact of building industry has led to a renewed interest in Earth Construction. Most of Earth Construction literature dealt with rammed Earth or adobe techniques, but very little with cob. Yet, cob participates in the diversity of vernacular Earth Construction processes that value local materials and is an alternative to rammed Earth and adobe in specific geographical conditions. Conservation of cob heritage also requires a better knowledge of this vernacular Construction process. This bibliographical analysis gathered extensive data on cob process and summarized the different cob process variations, attempting to take into account their diversity. This analysis allowed us to provide novel data on cob process, and more specifically, (1) a clear definition of cob with regard to other Earth Construction processes, (2) a first summarized description of cob process that clearly distinguished its variations, (3) a list of fibres traditionally employed, (4) values and, if possible, average and standard deviation for fibre length, fibre content, manufacture water content, drying times, lift heights and wall thicknesses, (5) a summary of the strategies to manage shrinkage cracks, (6) a criterion on the quality of implementation and/or Earth for cob, based on slenderness ration of lifts and (7) a discussion on the evolution of cob process with regard to societal evolutions.
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first exploratory study on dynamic characteristics of rammed Earth buildings
Engineering Structures, 2011Co-Authors: Q. B. Bui, Stephane Hans, Jean Claude MorelAbstract:Abstract Rammed Earth Construction is attracting a renewed interest throughout the world thanks to its “green” characteristics in the context of sustainable development. Several studies have been carried out to investigate this material and evaluate its durability along with its mechanical, thermal and Earthquake capacities. This paper presents a study on the parameters needed for the seismic design of rammed Earth buildings in accordance with current Earthquake standards. First, the dynamic parameters of buildings such as natural frequencies and damping ratios–which were necessary to determine the equivalent static seismic force–were identified using in-situ dynamic measurements. Then, these experimental values were compared with the values calculated by empirical formulas suggested in Eurocode 8 to demonstrate that these formulas were applicable for the cases of rammed Earth structures. Then, modeling was done to find a simple suitable model for rammed Earth structures. Laboratory experiments were developed to measure the Poisson’s ratio which was necessary for the models. The results provided by the shear-beam model were close to that of in-situ experiments, which showed a shearing behavior of rammed Earth structures. Elements which influenced the dynamic behavior of this structural type were also discussed. Understanding the dynamic characteristics of rammed Earth structures will help engineers in their design of new rammed Earth buildings but also in Earthquake analyses of existing rammed Earth buildings.
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compression behaviour of non industrial materials in civil engineering by three scale experiments the case of rammed Earth
Materials and Structures, 2009Co-Authors: Jean Claude Morel, Stephane Hans, Nicolas MeunierAbstract:In order to give an example of a scientific approach adapted to non-industrial materials, we chose to study a structural element: a load-bearing building wall made of rammed Earth material. Rammed Earth Construction is an ancient technique which is attracting renewed interest throughout the world today. Although rammed Earth is currently regarded as a promising material in the Construction sector in the context of sustainable development, it is still difficult to quantify its durability, as well as its thermal and mechanical performances, which discourages people from using it. This paper is devoted to the study of the last problem. Three different scales were studied. The first is the scale of in-situ walls. Dynamic measurements were carried out on site to determine the Eigen frequencies of the walls. The elastic modulus was determined from the frequencies measured by using a finite element model. The second is the scale of a representative volume element (RVE). Rammed Earth RVE samples with dimensions similar to those of the walls on site were manufactured and tested in the laboratory. Finally, at the last scale, called the micro-mechanical scale, tests were performed on equivalent compressed Earth blocks (CEBs), which can replace the rammed Earth RVE samples to facilitate laboratory tests.
Mirja Illikainen - One of the best experts on this subject based on the ideXlab platform.
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fly ash classification efficiency of electrostatic precipitators in fluidized bed combustion of peat wood and forest residues
Journal of Environmental Management, 2018Co-Authors: Katja Ohenoja, Valter Wigren, Jan Osterbacka, Mika Körkkö, Mirja IllikainenAbstract:The increasing use of biomasses in the production of electricity and heat results in an increased amount of burning residue, fly ash which disposal is becoming more and more restricted and expensive. Therefore, there is a great interest in utilizing fly ashes instead of just disposing of it. This study aimed to establish whether the utilization of fly ash from the fluidized bed combustion of peat, wood, and forest residues can be improved by electrostatic precipitator separation of sulfate, chloride, and some detrimental metals. Classification selectivity calculations of electrostatic precipitators for three different fuel mixtures from two different power plants were performed by using Nelson's and Karnis's selectivity indices. Results showed that all fly ashes behaved similarly in the electrostatic separation process SiO2 resulted in coarse fractions with Nelson's selectivity of 0.2 or more, while sulfate, chloride, and the studied detrimental metals (arsenic, cadmium, and lead) enriched into fine fractions with varying selectivity from 0.2 to 0.65. Overall, the results of this study suggest that it is possible to improve the utilization potential of fly ashes from fluidized bed combustion in concrete, fertilizer, and Earth Construction applications by using electrostatic precipitators for the fractionating of fly ashes in addition to their initial function of collecting fly ash particles from flue gases. The separation of the finer fractions (ESP 2 and 3) from ESP 1 field fly ash is recommended.
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effect of particle size distribution on the self hardening property of biomass peat fly ash from a bubbling fluidized bed combustion
Fuel Processing Technology, 2016Co-Authors: Katja Ohenoja, Valter Wigren, Jan Osterbacka, Pekka Tanskanen, Olli Peltosaari, Mirja IllikainenAbstract:Abstract An increasing amount of biomass fly ash is produced because of the increased usage of renewable energy sources. Therefore, novel applications in which biomass fly ashes can be utilized efficiently are required. One interesting option is to use biomass fly ashes in hardening applications, such as Earth Construction. In this study, the self-hardening of ground fly ash from a Finnish power plant with a bubbling fluidized bed boiler that burns forest industry residuals and peat was investigated. Fly ash was ground with three different mills, namely, tumbling ball mill, impact mill, and jet mill, to different particle size distributions. Results showed that the amount of reactive components for ground fly ash samples was more or less the same with the original sample, but the particle size distribution was different. Moreover, the water requirement for self-hardening samples was completely different depending on the grinding mechanism. When particle size distribution was wider (after ball and impact milling), the water requirement was much lower due to the better packing of the particles. A smaller water requirement also led to greater compressive strength even the fly ash samples were chemically and mineralogically the same. After ball milling, obtaining four times higher self-hardening compressive strength, from 5 MPa to 20 MPa, was possible. For jet milled fly ash, the particle size distribution was narrow due to the classifier in the mill, and the water requirement was high. Therefore, the packing and self-hardening compressive strength of jet milled fly ash was lower than that of impact and ball milled samples.
Rui André Martins Silva - One of the best experts on this subject based on the ideXlab platform.
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comparison of the performance of hydraulic lime and clay based grouts in the repair of rammed Earth
Construction and Building Materials, 2018Co-Authors: Rui André Martins Silva, Daniel V. Oliveira, Oriol Dominguezmartinez, Eduardo PereiraAbstract:Abstract Earth Constructions constitute an important part of the built heritage and are spread worldwide. Rammed Earth is among the most used Earth Construction techniques, though it exhibits a high seismic vulnerability. Nevertheless, the structural behaviour of rammed Earth structures is still insufficiently comprehended. Thus, the preservation of this built heritage requires exhaustive characterisation of its mechanical and structural behaviours, as well as the development and validation of adequate intervention solutions. In this context, this paper presents an experimental program aimed at evaluating the effectiveness of grout injection to repair cracks and at further characterising the in-plane shear behaviour of rammed Earth walls. The experimental program included the testing of rammed Earth wallets under diagonal compression, which were subsequently repaired with injection of a clay-based or a hydraulic lime-based grout, and retested. Furthermore, sonic tests were conducted on the wallets before the destructive tests. The obtained results allowed to highlight that both grouts led to similar repairing performances, though the interlocking contribution promoted by the coarse particles of the rammed Earth to the shear behaviour was found to be irrecoverable.
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evaluating the seismic behaviour of rammed Earth buildings from portugal from simple tools to advanced approaches
Engineering Structures, 2018Co-Authors: Rui André Martins Silva, Daniel V. Oliveira, Nuno Mendes, Antonio Romanazzi, Oriol Dominguezmartinez, Tiago F. S. MirandaAbstract:Abstract Despite the use of rammed Earth became marginal in the second half of the past century, Portugal still holds an important built heritage. Recently, a growing use of rammed Earth has been observed in modern Constructions, but it is putting aside the roots of traditional rammed Earth Construction. The seismic behaviour of rammed Earth buildings is still insufficiently comprehended, constituting a matter of great concern, since most of the traditional dwellings are built on regions with important seismic hazard. Moreover, the complex architecture of modern rammed Earth buildings is expected to make their seismic behaviour even more fragile. This paper intends to provide a better comprehension on the seismic behaviour of rammed Earth Constructions from Portugal. For this purpose, twenty traditional dwellings were evaluated on the basis of a simplified approach, while a modern Construction was investigated by means of destructive and non-destructive testing approaches. The main findings of these approaches are discussed in detail, but it can be highlighted that the architectural features of traditional rammed Earth buildings benefit their seismic behaviour, while the complex architecture of modern rammed Earth buildings demands using advanced engineering tools for their seismic assessment.
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rammed Earth Construction with granitic residual soils the case study of northern portugal
Construction and Building Materials, 2013Co-Authors: Rui André Martins Silva, Daniel V. Oliveira, Tiago F. S. Miranda, Nuno Cristelo, Maria C Escobar, Edgar SoaresAbstract:Abstract Building in unstabilised rammed Earth results in low environmental impact. However, northern Portugal has not historical tradition with this technique, and thus the suitability of the local granitic residual soils is unknown. This paper presents an experimental investigation, where this possibility is assessed. The results showed that these soils are unsuitable, and that rammed Earth Construction is only feasible if these soils go through a stabilising process. The alkaline activation of fly ash was investigated as an environmentally friendly stabilisation technique, and it proved to be capable of improving the performance of rammed Earth.
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soil stabilisation using alkaline activation of fly ash for self compacting rammed Earth Construction
Construction and Building Materials, 2012Co-Authors: Tiago F. S. Miranda, Daniel V. Oliveira, Nuno Cristelo, S Glendinning, Rui André Martins SilvaAbstract:Abstract This paper studies the effectiveness of alkaline activation of low-calcium fly ash on the improvement of residual granitic soils to be used on rammed-Earth Construction. Different liquid:solid ratios, alkali concentrations and Na 2 O:ash ratios were tested. Effect of calcium hydroxide, sodium chloride and concrete superplasticiser is also reported. Compressive strength up to 7 days at 60 °C was determined. Results show that there is an optimum value for the activator:solids ratio and the alkali concentration, and that a decrease in the Na 2 O:ash ratio results in a strength increase. No improvement was observed with the sodium chloride or the superplasticiser, while the calcium produced only a short term increase in strength. SEM/EDS analysis were used to analyse microstructural development, showing that strength is fairly related to the Si:Al and Na:Si ratios.
Katja Ohenoja - One of the best experts on this subject based on the ideXlab platform.
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fly ash classification efficiency of electrostatic precipitators in fluidized bed combustion of peat wood and forest residues
Journal of Environmental Management, 2018Co-Authors: Katja Ohenoja, Valter Wigren, Jan Osterbacka, Mika Körkkö, Mirja IllikainenAbstract:The increasing use of biomasses in the production of electricity and heat results in an increased amount of burning residue, fly ash which disposal is becoming more and more restricted and expensive. Therefore, there is a great interest in utilizing fly ashes instead of just disposing of it. This study aimed to establish whether the utilization of fly ash from the fluidized bed combustion of peat, wood, and forest residues can be improved by electrostatic precipitator separation of sulfate, chloride, and some detrimental metals. Classification selectivity calculations of electrostatic precipitators for three different fuel mixtures from two different power plants were performed by using Nelson's and Karnis's selectivity indices. Results showed that all fly ashes behaved similarly in the electrostatic separation process SiO2 resulted in coarse fractions with Nelson's selectivity of 0.2 or more, while sulfate, chloride, and the studied detrimental metals (arsenic, cadmium, and lead) enriched into fine fractions with varying selectivity from 0.2 to 0.65. Overall, the results of this study suggest that it is possible to improve the utilization potential of fly ashes from fluidized bed combustion in concrete, fertilizer, and Earth Construction applications by using electrostatic precipitators for the fractionating of fly ashes in addition to their initial function of collecting fly ash particles from flue gases. The separation of the finer fractions (ESP 2 and 3) from ESP 1 field fly ash is recommended.
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effect of particle size distribution on the self hardening property of biomass peat fly ash from a bubbling fluidized bed combustion
Fuel Processing Technology, 2016Co-Authors: Katja Ohenoja, Valter Wigren, Jan Osterbacka, Pekka Tanskanen, Olli Peltosaari, Mirja IllikainenAbstract:Abstract An increasing amount of biomass fly ash is produced because of the increased usage of renewable energy sources. Therefore, novel applications in which biomass fly ashes can be utilized efficiently are required. One interesting option is to use biomass fly ashes in hardening applications, such as Earth Construction. In this study, the self-hardening of ground fly ash from a Finnish power plant with a bubbling fluidized bed boiler that burns forest industry residuals and peat was investigated. Fly ash was ground with three different mills, namely, tumbling ball mill, impact mill, and jet mill, to different particle size distributions. Results showed that the amount of reactive components for ground fly ash samples was more or less the same with the original sample, but the particle size distribution was different. Moreover, the water requirement for self-hardening samples was completely different depending on the grinding mechanism. When particle size distribution was wider (after ball and impact milling), the water requirement was much lower due to the better packing of the particles. A smaller water requirement also led to greater compressive strength even the fly ash samples were chemically and mineralogically the same. After ball milling, obtaining four times higher self-hardening compressive strength, from 5 MPa to 20 MPa, was possible. For jet milled fly ash, the particle size distribution was narrow due to the classifier in the mill, and the water requirement was high. Therefore, the packing and self-hardening compressive strength of jet milled fly ash was lower than that of impact and ball milled samples.
Erwan Hamard - One of the best experts on this subject based on the ideXlab platform.
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A new methodology to identify and quantify material resource at a large scale for Earth Construction - Application to cob in Brittany
Construction and Building Materials, 2018Co-Authors: Erwan Hamard, Andry Razakamanantsoa, Bogdan Cazacliu, Blandine Lemercier, Jean Claude MorelAbstract:A new methodology based on the cross-referencing of spatialized pedological and heritage data is proposed to identify and quantify soil resources available for Earth Construction. The paper underlines the pedological particularities of areas containing Earth heritage and uses these particularities to propose criteria to assess the suitability of soils for modern Earth Construction. The methodology applied at the regional scale in France (for a given area of 27,200 km2 in Brittany) enabled to specify five new texture classes (balance between clay, silt, sand and gravel content) of suitability for cob soils. This result calls into question recommendations available in the literature. The methodology also provides data on the scale of availability of the resource to repair Earth built heritage (cob) or to build new low impact buildings with integrated modern cob walls. In the studied area the potential waste recovery of 2.8 Mt per year is measured, highlighting the large availability of materials for Earth Construction. At least 23% of Earthwork wastes of Brittany are suitable for Earth Construction (0.7 Mt). However, Earth remains a non-renewable material and this resource has to be properly managed, requiring an appropriate building design and maintenance in order to increase longevity and to avoid the use of admixture, preventing Earth reversibility at end of life.
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Historical rammed Earth process description thanks to micromorphological analysis
International Journal of Architectural Heritage, 2016Co-Authors: Erwan Hamard, Antonin Fabbri, Cécilia Cammas, Andry Razakamanantsoa, Bogdan Cazacliu, Jean Claude MorelAbstract:Rammed Earth was traditionally used in western European countries before industrial building materials replace it during 20th Century. Construction strategies developed by former builders were dictated by locally available Construction materials and engendered local constructive cultures. Unfortunately, this knowledge was orally transmitted and is lost today. The rediscovery of these cultures can provide answers to modern rammed Earth Construction processes. Micromorphological analysis of Earth walls provides information to rediscover traditional rammed Earth process. This methodology is applied for the first time, on a rammed Earth wall of a farm located in Bresse (France). Thanks to this methodology, pedological horizon, extraction depth and location of the material source are identified. The surface area excavated for the Construction of the building is estimated. Micromorphological study gives information on mixing degree and water content at implementation time. Strain features associated with ramming effect and rammed Earth boundary layer are also highlighted. Running Head: Rammed Earth micromorphological analysis
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Cob, a vernacular Earth Construction process in the context of modern sustainable building
Building and Environment, 2016Co-Authors: Erwan Hamard, Andry Razakamanantsoa, Bogdan Cazacliu, Jean Claude MorelAbstract:The will of reducing environmental and social impact of building industry has led to a renewed interest in Earth Construction. Most of Earth Construction literature dealt with rammed Earth or adobe techniques, but very little with cob. Yet, cob participates in the diversity of vernacular Earth Construction processes that value local materials and is an alternative to rammed Earth and adobe in specific geographical conditions. Conservation of cob heritage also requires a better knowledge of this vernacular Construction process. This bibliographical analysis gathered extensive data on cob process and summarized the different cob process variations, attempting to take into account their diversity. This analysis allowed us to provide novel data on cob process, and more specifically, (1) a clear definition of cob with regard to other Earth Construction processes, (2) a first summarized description of cob process that clearly distinguished its variations, (3) a list of fibres traditionally employed, (4) values and, if possible, average and standard deviation for fibre length, fibre content, manufacture water content, drying times, lift heights and wall thicknesses, (5) a summary of the strategies to manage shrinkage cracks, (6) a criterion on the quality of implementation and/or Earth for cob, based on slenderness ration of lifts and (7) a discussion on the evolution of cob process with regard to societal evolutions.
