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Phase development in normal and ultra high performance cementitious systems by quantitative X-ray analysis and thermoanalytical methods / A. Korpa in Cement and concrete research, Vol. 39 N° 2 (Fevrier 2009)  

Public ISBD [article]  inCement and concrete research > Vol. 39 N° 2 (Fevrier 2009) . - pp. 69–76 Titre : Phase development in normal and ultra high performance cementitious systems by quantitative X-ray analysis and thermoanalytical methods Type de document : texte imprimé Auteurs : A. Korpa, Auteur ; T. Kowald, Auteur ; R. Trettin, Auteur Année de publication : 2009 Article en page(s) : pp. 69–76 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Ultra high performance concrete (UHPC)  Pozzolanic reaction  Phase quantification  Quantitative X-ray diffraction  Thermogravimetry Résumé : Quantitative X-ray diffraction (QXRD) and thermogravimetry (TG) methods are used to determine the phase development up to 28 days of hydration in normal and ultra high performance cementitious systems (UHPC) that do not contain aggregate. The phase development in ultra high performance cementitious formulation is quantitatively and kinetically different from that in normal concrete formulation. This is related to the different components employed and their associated reactions. For both formulations the most remarkable changes of the phase contents are recorded between the first and second hydration day and up to the seventh day. After the seventh day less phase content changes are measured. Because of the non sufficient water amount for hydration, considerable amount of cement remains non hydrated in the UHPC formulation. The portlandite content, which is present in the UHPC specimen, gives evidence for non complete pozzolanic reactions even after 28 days of hydration, whereas the absence of calcite in the UHPC specimen indicates an insignificant carbonation in this specimen. ISSN : 0008-8846 En ligne : http://www.sciencedirect.com/science/article/pii/S0008884608002111 [article] Phase development in normal and ultra high performance cementitious systems by quantitative X-ray analysis and thermoanalytical methods [texte imprimé] / A. Korpa, Auteur ; T. Kowald, Auteur ; R. Trettin, Auteur . - 2009 . - pp. 69–76. Génie Civil Langues : Anglais (eng) in Cement and concrete research > Vol. 39 N° 2 (Fevrier 2009) . - pp. 69–76 Mots-clés : Ultra high performance concrete (UHPC)  Pozzolanic reaction  Phase quantification  Quantitative X-ray diffraction  Thermogravimetry Résumé : Quantitative X-ray diffraction (QXRD) and thermogravimetry (TG) methods are used to determine the phase development up to 28 days of hydration in normal and ultra high performance cementitious systems (UHPC) that do not contain aggregate. The phase development in ultra high performance cementitious formulation is quantitatively and kinetically different from that in normal concrete formulation. This is related to the different components employed and their associated reactions. For both formulations the most remarkable changes of the phase contents are recorded between the first and second hydration day and up to the seventh day. After the seventh day less phase content changes are measured. Because of the non sufficient water amount for hydration, considerable amount of cement remains non hydrated in the UHPC formulation. The portlandite content, which is present in the UHPC specimen, gives evidence for non complete pozzolanic reactions even after 28 days of hydration, whereas the absence of calcite in the UHPC specimen indicates an insignificant carbonation in this specimen. ISSN : 0008-8846 En ligne : http://www.sciencedirect.com/science/article/pii/S0008884608002111

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Roman cements — Belite cements calcined at low temperature / D.C. Hughes in Cement and concrete research, Vol. 39 N° 2 (Fevrier 2009)  

Public ISBD [article]  inCement and concrete research > Vol. 39 N° 2 (Fevrier 2009) . - pp. 77–89 Titre : Roman cements — Belite cements calcined at low temperature Type de document : texte imprimé Auteurs : D.C. Hughes, Auteur ; D. Jaglin, Auteur ; R. Kozłowski, Auteur Année de publication : 2009 Article en page(s) : pp. 77–89 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Characterisation  Compressive strength  Natural cement  Cement manufacture Résumé : Roman cement was a major material used in the architecture of the nineteenth and early twentieth century across Europe, until it was displaced by Portland cement, and is absent from the palette of materials from which conservationists may now select. Calcination of cement-stones and marls from six sites in Poland, Austria and the UK has been conducted. The resulting mineralogy is dependant upon the characteristics of the original feedstock and the calcination temperatures. The principal hydraulic components are belites and amorphous aluminates. The stable belites in cements calcined at lower temperatures are largely α/ C2S while β C2S is stabilised as the calcination temperature is increased. Other components include uncalcined remnants, lime, brownmillerite and gehlenite. Optimum cements, assessed by compressive strength, were produced at relatively low temperatures, typically in the region of 750 °C. Two strength development profiles have been observed. ISSN : 0008-8846 En ligne : http://www.sciencedirect.com/science/article/pii/S0008884608002147 [article] Roman cements — Belite cements calcined at low temperature [texte imprimé] / D.C. Hughes, Auteur ; D. Jaglin, Auteur ; R. Kozłowski, Auteur . - 2009 . - pp. 77–89. Génie Civil Langues : Anglais (eng) in Cement and concrete research > Vol. 39 N° 2 (Fevrier 2009) . - pp. 77–89 Mots-clés : Characterisation  Compressive strength  Natural cement  Cement manufacture Résumé : Roman cement was a major material used in the architecture of the nineteenth and early twentieth century across Europe, until it was displaced by Portland cement, and is absent from the palette of materials from which conservationists may now select. Calcination of cement-stones and marls from six sites in Poland, Austria and the UK has been conducted. The resulting mineralogy is dependant upon the characteristics of the original feedstock and the calcination temperatures. The principal hydraulic components are belites and amorphous aluminates. The stable belites in cements calcined at lower temperatures are largely α/ C2S while β C2S is stabilised as the calcination temperature is increased. Other components include uncalcined remnants, lime, brownmillerite and gehlenite. Optimum cements, assessed by compressive strength, were produced at relatively low temperatures, typically in the region of 750 °C. Two strength development profiles have been observed. ISSN : 0008-8846 En ligne : http://www.sciencedirect.com/science/article/pii/S0008884608002147

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Research on the preparation of reversibly thermochromic cement based materials at normal temperature / Yiping Ma in Cement and concrete research, Vol. 39 N° 2 (Fevrier 2009)  

Public ISBD [article]  inCement and concrete research > Vol. 39 N° 2 (Fevrier 2009) . - pp. 90–94 Titre : Research on the preparation of reversibly thermochromic cement based materials at normal temperature Type de document : texte imprimé Auteurs : Yiping Ma, Auteur ; Beirong Zhu, Auteur Année de publication : 2009 Article en page(s) : pp. 90–94 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Reversibly thermochromic at normal temperature  Cement  Thermal environment for buildings Résumé : In this paper, reversibly thermochromic cement at normal temperature was prepared by adding reversibly thermochromic microcapsules in white Portland cement. The research results showed that the color of the reversibly thermochromic cement added with a kind of blue reversibly thermochromic microcapsule with 30 °C switching temperature (B30, in which B is for the blue color, 30 is for the switching temperature, and the similar way is used in the following of the paper) could be changed reversibly from blue at lower temperature to white at higher temperature, and the switching temperature was about 42 °C. When added with a kind of red reversibly thermochromic microcapsule with 30 °C switching temperature (R30) or a kind of green reversibly thermochromic microcapsule with 30 °C switching temperature (G30), the color could be reversibly changed from red or green to white, and the switching temperature was about 58 °C. The kind of red reversibly thermochromic microcapsule could thus meet the needs of warm tone in winter and cool tone in summer in buildings. When the thermochromic microcapsule B30 was added in white Portland cement, the water content of the standard consistence of cement slurry increased by about 13%, and the mechanical properties, such as flexural strength and compressive strength, decreased by 20%–40%, but the setting time and the soundness of cement were not affected. All the research results indicate that the prepared material could meet the demand for creation of thermally comfortable environment of buildings. Through changing the solvent, the thermochromic microcapsule R5, G5 and B5 etc. were prepared further. Then by mixed 10% R5, G5 and B5 with white Portland cement, the switching temperatures could be lowered down to 26 °C, 26 °C and 17 °C respectively. The thermal effect of improved reversibly thermochromic cement based material (white cement mixed with 10% black microcapsule, and its switching temperature was about 24 °C) showed that it could warm buildings in winter and avoid buildings over-heated in summer. ISSN : 0008-8846 En ligne : http://www.sciencedirect.com/science/article/pii/S0008884608001968 [article] Research on the preparation of reversibly thermochromic cement based materials at normal temperature [texte imprimé] / Yiping Ma, Auteur ; Beirong Zhu, Auteur . - 2009 . - pp. 90–94. Génie Civil Langues : Anglais (eng) in Cement and concrete research > Vol. 39 N° 2 (Fevrier 2009) . - pp. 90–94 Mots-clés : Reversibly thermochromic at normal temperature  Cement  Thermal environment for buildings Résumé : In this paper, reversibly thermochromic cement at normal temperature was prepared by adding reversibly thermochromic microcapsules in white Portland cement. The research results showed that the color of the reversibly thermochromic cement added with a kind of blue reversibly thermochromic microcapsule with 30 °C switching temperature (B30, in which B is for the blue color, 30 is for the switching temperature, and the similar way is used in the following of the paper) could be changed reversibly from blue at lower temperature to white at higher temperature, and the switching temperature was about 42 °C. When added with a kind of red reversibly thermochromic microcapsule with 30 °C switching temperature (R30) or a kind of green reversibly thermochromic microcapsule with 30 °C switching temperature (G30), the color could be reversibly changed from red or green to white, and the switching temperature was about 58 °C. The kind of red reversibly thermochromic microcapsule could thus meet the needs of warm tone in winter and cool tone in summer in buildings. When the thermochromic microcapsule B30 was added in white Portland cement, the water content of the standard consistence of cement slurry increased by about 13%, and the mechanical properties, such as flexural strength and compressive strength, decreased by 20%–40%, but the setting time and the soundness of cement were not affected. All the research results indicate that the prepared material could meet the demand for creation of thermally comfortable environment of buildings. Through changing the solvent, the thermochromic microcapsule R5, G5 and B5 etc. were prepared further. Then by mixed 10% R5, G5 and B5 with white Portland cement, the switching temperatures could be lowered down to 26 °C, 26 °C and 17 °C respectively. The thermal effect of improved reversibly thermochromic cement based material (white cement mixed with 10% black microcapsule, and its switching temperature was about 24 °C) showed that it could warm buildings in winter and avoid buildings over-heated in summer. ISSN : 0008-8846 En ligne : http://www.sciencedirect.com/science/article/pii/S0008884608001968

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Bulk magnetic susceptibility measurements for determination of fly ash presence in concrete / F.J. Presuel-Moreno in Cement and concrete research, Vol. 39 N° 2 (Fevrier 2009)  

Public ISBD [article]  inCement and concrete research > Vol. 39 N° 2 (Fevrier 2009) . - pp. 95–101 Titre : Bulk magnetic susceptibility measurements for determination of fly ash presence in concrete Type de document : texte imprimé Auteurs : F.J. Presuel-Moreno, Auteur ; A.A. Sagüés, Auteur Année de publication : 2009 Article en page(s) : pp. 95–101 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Fly ash  Magnetic susceptibility  Apparent diffusivity  Chloride  properties Résumé : Reproducible measurements of magnetic susceptibility χm of laboratory and field extracted concrete core samples were achieved with simple instrumentation. There was a nearly linear relationship between χm and the mass of fly ash per unit volume, or its volume fraction. The magnetic response of a given FA was not significantly affected by the process of curing and subsequent evolution of the concrete over two years, or by carbonation of the concrete. Field extracted concrete cores exhibited a wide range of χm values. The group of specimens with the highest values of χm also had the lowest chloride ion diffusivity, consistent with the presence of admixed FA. Conversely, specimens with nil magnetic response included those from concrete with the highest chloride diffusivity. The magnetic measurements provided reasonable order-of-magnitude indications of FA presence in field extracted cores. However, precise determination of FA content from magnetic measurements of field cores does not appear feasible in the absence of additional information. ISSN : 0008-8846 En ligne : http://www.sciencedirect.com/science/article/pii/S0008884608002135 [article] Bulk magnetic susceptibility measurements for determination of fly ash presence in concrete [texte imprimé] / F.J. Presuel-Moreno, Auteur ; A.A. Sagüés, Auteur . - 2009 . - pp. 95–101. Génie Civil Langues : Anglais (eng) in Cement and concrete research > Vol. 39 N° 2 (Fevrier 2009) . - pp. 95–101 Mots-clés : Fly ash  Magnetic susceptibility  Apparent diffusivity  Chloride  properties Résumé : Reproducible measurements of magnetic susceptibility χm of laboratory and field extracted concrete core samples were achieved with simple instrumentation. There was a nearly linear relationship between χm and the mass of fly ash per unit volume, or its volume fraction. The magnetic response of a given FA was not significantly affected by the process of curing and subsequent evolution of the concrete over two years, or by carbonation of the concrete. Field extracted concrete cores exhibited a wide range of χm values. The group of specimens with the highest values of χm also had the lowest chloride ion diffusivity, consistent with the presence of admixed FA. Conversely, specimens with nil magnetic response included those from concrete with the highest chloride diffusivity. The magnetic measurements provided reasonable order-of-magnitude indications of FA presence in field extracted cores. However, precise determination of FA content from magnetic measurements of field cores does not appear feasible in the absence of additional information. ISSN : 0008-8846 En ligne : http://www.sciencedirect.com/science/article/pii/S0008884608002135

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Cementitious and pozzolanic behavior of electric arc furnace steel slags / Luckman Muhmood in Cement and concrete research, Vol. 39 N° 2 (Fevrier 2009)  

Public ISBD [article]  inCement and concrete research > Vol. 39 N° 2 (Fevrier 2009) . - pp.102–109 Titre : Cementitious and pozzolanic behavior of electric arc furnace steel slags Type de document : texte imprimé Auteurs : Luckman Muhmood, Auteur ; Satish Vitta, Auteur ; D. Venkateswaran, Auteur Année de publication : 2009 Article en page(s) : pp.102–109 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Hydration  Pozzolanic  Compressive strength  Slag Résumé : The cementitious and pozzolanic behavior of electric arc furnace steel slag, both as received and treated has been studied in detail. The as received slag was completely crystalline and multi-phasic with Fe-substituted monticellite as the predominant phase. Treatment of this slag, remelting and water quenching, results in reduction of Fe-oxide content coupled with an increase in basicity index which makes it more hydraulic compared to the as received slag. The remelted slag has several phases with merwinite as the dominant phase. Thermal analysis of the hydrated slag shows that treating the as received slag increases the water absorption capacity, a property essential for cementitious behavior. Compression strength of the slag blended cements was studied and it was found that substitution of 20% ground granulated blast furnace slag with electric arc furnace steel slag does not decrease the strength beyond 28 days. The control cement has a strength of 58.6 MPa compared to 58 MPa for the cement comprising of 20% untreated slag. The substitution of this untreated slag with treated slag exhibits the highest strength, 61 MPa and a potential for further strength increase after 28 days. In the case of cement mix with no blast furnace slag, substitution of 15% clinker with steel slag does not decrease the strength significantly, 64.4 MPa compared to 66.5 MPa for the control cement. Substituting 30% clinker in the cement mix with electric arc furnace slag however results in significant decrease in strength, 53.4 MPa. The pozzolanic strength of the slag was found to increase significantly due to remelting from 2.0 MPa for the as received slag to 8.0 MPa for the treated slag. ISSN : 0008-8846 En ligne : http://www.sciencedirect.com/science/article/pii/S0008884608002093 [article] Cementitious and pozzolanic behavior of electric arc furnace steel slags [texte imprimé] / Luckman Muhmood, Auteur ; Satish Vitta, Auteur ; D. Venkateswaran, Auteur . - 2009 . - pp.102–109. Génie Civil Langues : Anglais (eng) in Cement and concrete research > Vol. 39 N° 2 (Fevrier 2009) . - pp.102–109 Mots-clés : Hydration  Pozzolanic  Compressive strength  Slag Résumé : The cementitious and pozzolanic behavior of electric arc furnace steel slag, both as received and treated has been studied in detail. The as received slag was completely crystalline and multi-phasic with Fe-substituted monticellite as the predominant phase. Treatment of this slag, remelting and water quenching, results in reduction of Fe-oxide content coupled with an increase in basicity index which makes it more hydraulic compared to the as received slag. The remelted slag has several phases with merwinite as the dominant phase. Thermal analysis of the hydrated slag shows that treating the as received slag increases the water absorption capacity, a property essential for cementitious behavior. Compression strength of the slag blended cements was studied and it was found that substitution of 20% ground granulated blast furnace slag with electric arc furnace steel slag does not decrease the strength beyond 28 days. The control cement has a strength of 58.6 MPa compared to 58 MPa for the cement comprising of 20% untreated slag. The substitution of this untreated slag with treated slag exhibits the highest strength, 61 MPa and a potential for further strength increase after 28 days. In the case of cement mix with no blast furnace slag, substitution of 15% clinker with steel slag does not decrease the strength significantly, 64.4 MPa compared to 66.5 MPa for the control cement. Substituting 30% clinker in the cement mix with electric arc furnace slag however results in significant decrease in strength, 53.4 MPa. The pozzolanic strength of the slag was found to increase significantly due to remelting from 2.0 MPa for the as received slag to 8.0 MPa for the treated slag. ISSN : 0008-8846 En ligne : http://www.sciencedirect.com/science/article/pii/S0008884608002093

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Ultrafine grinding of sugar cane bagasse ash for application as pozzolanic admixture in concrete / Guilherme Chagas Cordeiroa in Cement and concrete research, Vol. 39 N° 2 (Fevrier 2009)  

Public ISBD [article]  inCement and concrete research > Vol. 39 N° 2 (Fevrier 2009) . - pp. 110–115 Titre : Ultrafine grinding of sugar cane bagasse ash for application as pozzolanic admixture in concrete Type de document : texte imprimé Auteurs : Guilherme Chagas Cordeiroa, Auteur Année de publication : 2009 Article en page(s) : pp. 110–115 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Sugar cane bagasse ash  Pozzolan  Grinding  Particle size distribution  High-performance concrete Résumé : Sugar cane bagasse ash, a byproduct of sugar and alcohol production, is a potential pozzolanic material. However, its effective application in mortar and concrete requires first the controlled use of grinding and classification processes to allow it to achieve the fineness and homogeneity that are required to meet industry standards. The present paper investigates the role of mill type and grinding circuit configuration in grinding in laboratory- and pilot plant-scale on the particle size, specific surface area and pozzolanic activity of the produced ashes. It was observed that, although different size distributions were produced by the different mills and milling configurations, the pozzolanic activity of the ground ash was directly correlated to its fineness, characterized by its 80% passing size or Blaine specific surface area. From a low pozzolanic activity of less than 50% of the as-received ash, values above 100% could be reached after prolonged grinding times. Electric power requirements to reach the minimum pozzolanic activity were estimated to be in the order of 42 kWh/t in an industrial ball mill. Incorporation of an ultrafinely-ground ash in a high-performance concrete in partial replacement of Portland cement (10, 15 and 20% by mass) resulted in no measurable change in mechanical behavior, but improved rheology and resistance to penetration of chloride ions. ISSN : 0008-8846 En ligne : http://www.sciencedirect.com/science/article/pii/S0008884608002159 [article] Ultrafine grinding of sugar cane bagasse ash for application as pozzolanic admixture in concrete [texte imprimé] / Guilherme Chagas Cordeiroa, Auteur . - 2009 . - pp. 110–115. Génie Civil Langues : Anglais (eng) in Cement and concrete research > Vol. 39 N° 2 (Fevrier 2009) . - pp. 110–115 Mots-clés : Sugar cane bagasse ash  Pozzolan  Grinding  Particle size distribution  High-performance concrete Résumé : Sugar cane bagasse ash, a byproduct of sugar and alcohol production, is a potential pozzolanic material. However, its effective application in mortar and concrete requires first the controlled use of grinding and classification processes to allow it to achieve the fineness and homogeneity that are required to meet industry standards. The present paper investigates the role of mill type and grinding circuit configuration in grinding in laboratory- and pilot plant-scale on the particle size, specific surface area and pozzolanic activity of the produced ashes. It was observed that, although different size distributions were produced by the different mills and milling configurations, the pozzolanic activity of the ground ash was directly correlated to its fineness, characterized by its 80% passing size or Blaine specific surface area. From a low pozzolanic activity of less than 50% of the as-received ash, values above 100% could be reached after prolonged grinding times. Electric power requirements to reach the minimum pozzolanic activity were estimated to be in the order of 42 kWh/t in an industrial ball mill. Incorporation of an ultrafinely-ground ash in a high-performance concrete in partial replacement of Portland cement (10, 15 and 20% by mass) resulted in no measurable change in mechanical behavior, but improved rheology and resistance to penetration of chloride ions. ISSN : 0008-8846 En ligne : http://www.sciencedirect.com/science/article/pii/S0008884608002159

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Chloride-induced corrosion products of steel in cracked-concrete subjected to different loading conditions / Shahzma J. Jaffer in Cement and concrete research, Vol. 39 N° 2 (Fevrier 2009)  

Public ISBD [article]  inCement and concrete research > Vol. 39 N° 2 (Fevrier 2009) . - pp. 116–125 Titre : Chloride-induced corrosion products of steel in cracked-concrete subjected to different loading conditions Type de document : texte imprimé Auteurs : Shahzma J. Jaffer, Auteur ; Carolyn M. Hansson, Auteur Année de publication : 2009 Article en page(s) : pp. 116–125 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Crack  SEM  Corrosion Chloride Concrete Résumé : This project focused on examining the composition and distribution of chloride-induced corrosion products at the rebar–concrete interfaces and on crack surfaces in reinforced ordinary Portland cement concrete (OPCC) and high performance concrete (HPC) subjected to different loading conditions. The results indicated that, regardless of the type of loading, there was a larger distribution of corrosion products along the rebar surface in the HPC than in the OPCC. Also, dynamic loading caused a greater detachment of the aggregate–paste bond in OPCC than static loading. The opening and closing of the cracks in salt solution under dynamic load forced corrosion products to flow from the rebar–concrete interface into the cracks in both OPCC and HPC. As a result, corrosion products diffused from the crack into the cement paste in the dynamically loaded OPCC but remained in the cracks in the dynamically loaded HPC, where they induced branched cracks. The mill-scale on the rebar was also evaluated before and after being embedded in concrete and was observed to be porous allowing ingress of species from the cement paste. ISSN : 0008-8846 En ligne : http://www.sciencedirect.com/science/article/pii/S000888460800210X [article] Chloride-induced corrosion products of steel in cracked-concrete subjected to different loading conditions [texte imprimé] / Shahzma J. Jaffer, Auteur ; Carolyn M. Hansson, Auteur . - 2009 . - pp. 116–125. Génie Civil Langues : Anglais (eng) in Cement and concrete research > Vol. 39 N° 2 (Fevrier 2009) . - pp. 116–125 Mots-clés : Crack  SEM  Corrosion Chloride Concrete Résumé : This project focused on examining the composition and distribution of chloride-induced corrosion products at the rebar–concrete interfaces and on crack surfaces in reinforced ordinary Portland cement concrete (OPCC) and high performance concrete (HPC) subjected to different loading conditions. The results indicated that, regardless of the type of loading, there was a larger distribution of corrosion products along the rebar surface in the HPC than in the OPCC. Also, dynamic loading caused a greater detachment of the aggregate–paste bond in OPCC than static loading. The opening and closing of the cracks in salt solution under dynamic load forced corrosion products to flow from the rebar–concrete interface into the cracks in both OPCC and HPC. As a result, corrosion products diffused from the crack into the cement paste in the dynamically loaded OPCC but remained in the cracks in the dynamically loaded HPC, where they induced branched cracks. The mill-scale on the rebar was also evaluated before and after being embedded in concrete and was observed to be porous allowing ingress of species from the cement paste. ISSN : 0008-8846 En ligne : http://www.sciencedirect.com/science/article/pii/S000888460800210X

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Improvement of the chloride ingress resistance of OPC mortars by using spent cracking catalyst / E. Zornoza in Cement and concrete research, Vol. 39 N° 2 (Fevrier 2009)  

Public ISBD [article]  inCement and concrete research > Vol. 39 N° 2 (Fevrier 2009) . - pp. 126–139 Titre : Improvement of the chloride ingress resistance of OPC mortars by using spent cracking catalyst Type de document : texte imprimé Auteurs : E. Zornoza, Auteur ; P. Garcés, Auteur ; R. J. Payá, Auteur Année de publication : 2009 Article en page(s) : pp. 126–139 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Transport properties  Chloride  Pozzolan  Mortar  Corrosion Résumé : The influence of the incorporation of spent cracking catalyst (FC3R) on the chloride ingress resistance has been evaluated. Thermogravimetric analyses have shown that the pozzolanic reaction of FC3R yields higher contents of hydrated calcium aluminates and silicoaluminates, so chloride binding capacity of mortars was highly improved. Mercury intrusion porosimetry analyses demonstrated that FC3R produces a significant reduction of capillary pore volume. As a result non-steady-state and steady-state chloride diffusion coefficients were reduced, enhancing the chloride ingress resistance of mortars incorporating FC3R. Additionally, the corrosion behaviour of steel embedded in Portland cement mortars partially substituted by spent cracking catalyst (FC3R) under chloride attack has been studied. Results showed that the incorporation of FC3R decreased the corrosion rates of steels and increased chloride thresholds for corrosion. For this reason, FC3R is an interesting pozzolanic material that can be used in reinforced concrete for civil engineering applications exposed to the action of chlorides. ISSN : 0008-8846 En ligne : http://www.sciencedirect.com/science/article/pii/S0008884608002160 [article] Improvement of the chloride ingress resistance of OPC mortars by using spent cracking catalyst [texte imprimé] / E. Zornoza, Auteur ; P. Garcés, Auteur ; R. J. Payá, Auteur . - 2009 . - pp. 126–139. Génie Civil Langues : Anglais (eng) in Cement and concrete research > Vol. 39 N° 2 (Fevrier 2009) . - pp. 126–139 Mots-clés : Transport properties  Chloride  Pozzolan  Mortar  Corrosion Résumé : The influence of the incorporation of spent cracking catalyst (FC3R) on the chloride ingress resistance has been evaluated. Thermogravimetric analyses have shown that the pozzolanic reaction of FC3R yields higher contents of hydrated calcium aluminates and silicoaluminates, so chloride binding capacity of mortars was highly improved. Mercury intrusion porosimetry analyses demonstrated that FC3R produces a significant reduction of capillary pore volume. As a result non-steady-state and steady-state chloride diffusion coefficients were reduced, enhancing the chloride ingress resistance of mortars incorporating FC3R. Additionally, the corrosion behaviour of steel embedded in Portland cement mortars partially substituted by spent cracking catalyst (FC3R) under chloride attack has been studied. Results showed that the incorporation of FC3R decreased the corrosion rates of steels and increased chloride thresholds for corrosion. For this reason, FC3R is an interesting pozzolanic material that can be used in reinforced concrete for civil engineering applications exposed to the action of chlorides. ISSN : 0008-8846 En ligne : http://www.sciencedirect.com/science/article/pii/S0008884608002160

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