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3 results on '"Mohamad Al Shamaa"'

1. Influence of relative humidity on delayed ettringite formation

Author

Mohamad Al Shamaa, Loic Divet, Georges Nahas, Stéphane Lavaud, Jean-Michel Torrenti, Institut de Radioprotection et de Sûreté Nucléaire (IRSN), Comportement Physico-chimique et Durabilité des Matériaux (IFSTTAR/MAST/CPDM), Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Communauté Université Paris-Est, Département Matériaux et Structures (IFSTTAR/MAST), Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-PRES Université Paris-Est, Laboratoire de Mécanique et Technologie (LMT), École normale supérieure - Cachan (ENS Cachan)-Centre National de la Recherche Scientifique (CNRS), Matériaux pour Infrastructure de Transport (IFSTTAR/MAST/MIT), PRES Université Nantes Angers Le Mans (UNAM)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR), Division Physico-chimie des Matériaux (LCPC/PCM), Laboratoire Central des Ponts et Chaussées (LCPC)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12), and Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-PRES Université Nantes Angers Le Mans (UNAM)-PRES Université Paris-Est

Subjects
Ettringite, Materials science, TENEUR EN EAU, PROPRIETE MECANIQUE, PERMEABILITE, [SPI.MAT]Engineering Sciences [physics]/Materials, [SPI]Engineering Sciences [physics], chemistry.chemical_compound, [SPI.MECA.MEMA]Engineering Sciences [physics]/Mechanics [physics.med-ph]/Mechanics of materials [physics.class-ph], Dynamic modulus, BETON, medicine, FORMATION DIFFEREE D'ETTRINGITE, General Materials Science, Relative humidity, Composite material, Porosity, ComputingMilieux_MISCELLANEOUS, ALCALI REACTION, BETON JEUNE, HUMIDITE, Building and Construction, Permeability (earth sciences), chemistry, Swelling, medicine.symptom
Abstract

This experimental study aims to determine the effect of relative humidity on concrete expansion due to delayed ettringite formation (DEF), which still remains imperfectly known. Test methods were designed to trigger reaction in concrete specimens and determine how ambient RH affects expansion of the specimens. Saturated salts solutions were used to achieve distinct ambient RH conditions within containers. Also, chemical analysis was performed to determine and quantify the fractions of alkalis leaching out of the pore solutions of concretes. Results showed that the critical ambient RH value that corresponds to significant suppression of DEF could be greatly dependent on the alkalis fractions leached out. Finally, the consequences of swelling due to DEF on the concrete properties are assessed. After swelling, both of gas permeability and porosity was increased significantly and dynamic modulus was reduced by about 45%.

Published
2015
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2. Coupling between mechanical and transfer properties and expansion due to DEF in a concrete of a nuclear power plant

Author

Georges Nahas, Stéphane Lavaud, Loic Divet, Jean-Michel Torrenti, Mohamad Al Shamaa, Institut de Radioprotection et de Sûreté Nucléaire (IRSN), Comportement Physico-chimique et Durabilité des Matériaux (IFSTTAR/MAST/CPDM), Communauté Université Paris-Est-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR), Département Matériaux et Structures (IFSTTAR/MAST), Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-PRES Université Paris-Est, Laboratoire de Mécanique et Technologie (LMT), École normale supérieure - Cachan (ENS Cachan)-Centre National de la Recherche Scientifique (CNRS), Matériaux pour Infrastructure de Transport (IFSTTAR/MAST/MIT), Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-PRES Université Nantes Angers Le Mans (UNAM), Division Physico-chimie des Matériaux (LCPC/PCM), Laboratoire Central des Ponts et Chaussées (LCPC)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12), and Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-PRES Université Nantes Angers Le Mans (UNAM)-PRES Université Paris-Est

Subjects
Nuclear and High Energy Physics, Ettringite, Materials science, 0211 other engineering and technologies, 02 engineering and technology, 7. Clean energy, PERMEABILITE, law.invention, [SPI]Engineering Sciences [physics], chemistry.chemical_compound, CENTRALE NUCLEAIRE, law, 021105 building & construction, Nuclear power plant, medicine, Coupling (piping), General Materials Science, Composite material, Safety, Risk, Reliability and Quality, Waste Management and Disposal, ComputingMilieux_MISCELLANEOUS, business.industry, BETON JEUNE, Mechanical Engineering, Foundation (engineering), Structural engineering, 021001 nanoscience & nanotechnology, Permeability (earth sciences), Nuclear Energy and Engineering, Properties of concrete, chemistry, Containment, ETTRINGITE, Swelling, medicine.symptom, 0210 nano-technology, business
Abstract

This paper focuses on studying the consequences of expansion due to delayed ettringite formation (DEF) on transfer and mechanical properties of concrete in the case of nuclear structures. It concerns a concrete representative of a containment vessel of a nuclear power plant where temperature variations at early age are very large. An experimental heat treatment, representative of the temperature history in the raft foundation of the containment vessel was reproduced after a modeling of its temperature rise. After this treatment, concrete exhibits swelling due to the development of DEF. The gas permeability is increased significantly after swelling, and the safety requirements expected by these structures are thus affected.

Published
2014
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3. Influence of limestone filler and of the size of the aggregates on DEF

Author

Jean-Baptiste Colliat, Mohamad Al Shamaa, Stéphane Lavaud, Jean-Michel Torrenti, Loic Divet, Georges Nahas, Institut de Radioprotection et de Sûreté Nucléaire (IRSN), Comportement Physico-chimique et Durabilité des Matériaux (IFSTTAR/MAST/CPDM), Communauté Université Paris-Est-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR), Laboratoire de Mécanique de Lille - FRE 3723 (LML), Université de Lille, Sciences et Technologies-Centrale Lille-Centre National de la Recherche Scientifique (CNRS), Université de Lille, Sciences et Technologies, Département Matériaux et Structures (IFSTTAR/MAST), Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-PRES Université Paris-Est, Matériaux pour Infrastructure de Transport (IFSTTAR/MAST/MIT), Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-PRES Université Nantes Angers Le Mans (UNAM), Division Physico-chimie des Matériaux (LCPC/PCM), Laboratoire Central des Ponts et Chaussées (LCPC)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12), Laboratoire de Mécanique et Technologie (LMT), École normale supérieure - Cachan (ENS Cachan)-Centre National de la Recherche Scientifique (CNRS), Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-PRES Université Nantes Angers Le Mans (UNAM)-PRES Université Paris-Est, and Université de Lille, Sciences et Technologies-Ecole Centrale de Lille-Université de Lille-Centre National de la Recherche Scientifique (CNRS)

Subjects
Filler (packaging), Ettringite, Water uptake, Materials science, Kinetics, 0211 other engineering and technologies, Delayed ettringite formation, FOS: Physical sciences, 020101 civil engineering, 02 engineering and technology, 0201 civil engineering, law.invention, Aggregate size, chemistry.chemical_compound, [SPI]Engineering Sciences [physics], law, 021105 building & construction, medicine, Carboaluminates, General Materials Science, Composite material, Swelling, ComputingMilieux_MISCELLANEOUS, Limestone filler, Condensed Matter - Materials Science, Materials Science (cond-mat.mtrl-sci), Building and Construction, Portland cement, [SPI.GCIV]Engineering Sciences [physics]/Civil Engineering, chemistry, Volume fraction, medicine.symptom, Mortar, Concrete
Abstract

This experimental study aims to determine the effect of limestone filler on concrete expansion due to delayed ettringite formation (DEF). Different mortars made with different sizes and percentages of limestone filler and Portland cement CEM I 52.5N are conserved in water. The expansion of the specimens is measured. Results show that DEF is not inhibited by limestone filler. The kinetics and the amplitude of the swelling depend on the size of the limestone filler. The volume fraction of aggregates changes only the kinetics: the relation between swelling and water uptake depends only on the size of the aggregates., 16 pages, 9 figures, 4 tables

Published
2016
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