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1 to 50 of 926 results
  • Bioreceptivity evaluation of cementitious materials designed to stimulate biological growth

     Manso Blanco, Sandra; De Muynck, Willem; Segura Pérez, Ignacio; Aguado De Cea, Antonio; Steppe, Kathy; Boon, Nico; de Belie, Nele
    Science of the total environment
    Date of publication: 2014-02-09
    Journal article

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    Ordinary Portland cement (OPC), the most used binder in construction, presents some disadvantages in terms of pollution (CO2 emissions) and visual impact. For this reason, green roofs and façades have gain considerable attention in the last decade as a way to integrate nature in cities. These systems, however, suffer from high initial and maintenance costs. An alternative strategy to obtain green facades is the direct natural colonisation of the cementitious construction materials constituting the wall, a phenomenon governed by the bioreceptivity of such material. This work aims at assessing the suitability of magnesium phosphate cement (MPC) materials to allow a rapid natural colonisation taking carbonated OPC samples as a reference material. For that, the aggregate size, the w/c ratio and the amount of cement paste of mortars made of both binders were modified. The assessment of the different bioreceptivities was conducted by means of an accelerated algal fouling test. MPC samples exhibited a faster fouling compared to OPC samples, which could be mainly attributed to the lower pH of the MPC binder. In addition to the binder, the fouling rate was governed by the roughness and the porosity of the material. MPC mortar with moderate porosity and roughness appears to be the most feasible material to be used for the development of green concrete walls.

    Ordinary Portland cement (OPC), the most used binder in construction, presents some disadvantages in terms of pollution (CO2 emissions) and visual impact. For this reason, green roofs and façades have gain considerable attention in the last decade as a way to integrate nature in cities. These systems, however, suffer from high initial and maintenance costs. An alternative strategy to obtain green facades is the direct natural colonisation of the cementitious construction materials constituting the wall, a phenomenon governed by the bioreceptivity of such material. This work aims at assessing the suitability of magnesium phosphate cement (MPC) materials to allow a rapid natural colonisation taking carbonated OPC samples as a reference material. For that, the aggregate size, the w/c ratio and the amount of cement paste of mortars made of both binders were modified. The assessment of the different bioreceptivities was conducted by means of an accelerated algal fouling test. MPC samples exhibited a faster fouling compared to OPC samples, which could be mainly attributed to the lower pH of the MPC binder. In addition to the binder, the fouling rate was governed by the roughness and the porosity of the material. MPC mortar with moderate porosity and roughness appears to be the most feasible material to be used for the development of green concrete walls.

  • Plastic fibres as the only reinforcement for flat suspended slabs: Experimental investigation and numerical simulation

     Pujadas Alvarez, Pablo; Blanco Álvarez, Ana; Pialarissi Cavalaro, Sergio Henrique; Aguado De Cea, Antonio
    Construction & building materials
    Date of publication: 2014-01-27
    Journal article

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    This paper focuses on the study of the structural response of hyperstatic concrete flat suspended slabs reinforced only with structural plastic macro-fibres. First, the experimental program is described and then the results obtained are presented. The slabs tested maintained a high load level after cracking showing a ductile behaviour with great stress redistribution capacity. Next, the tests were simulated by means of a finite element software with constitutive models according to the specifications of RILEM and the Spanish Structural Concrete Code (EHE). The numerical results in terms of load/mid-span deflection were compared with the experimental results. The predictions provided by the codes and guideline models clearly overestimated the experimental results, which suggests the need to review the constitutive models used for plastic fibre-reinforced concrete

    This paper focuses on the study of the structural response of hyperstatic concrete flat suspended slabs reinforced only with structural plastic macro-fibres. First, the experimental program is described and then the results obtained are presented. The slabs tested maintained a high load level after cracking showing a ductile behaviour with great stress redistribution capacity. Next, the tests were simulated by means of a finite element software with constitutive models according to the specifications of RILEM and the Spanish Structural Concrete Code (EHE). The numerical results in terms of load/mid-span deflection were compared with the experimental results. The predictions provided by the codes and guideline models clearly overestimated the experimental results, which suggests the need to review the constitutive models used for plastic fibre-reinforced concrete

  • Hormigones autocompactantes de resistencias medias

     Rodríguez Viacava, Iliana; Pialarissi Cavalaro, Sergio Henrique; Rodríguez de Sensale, Gemma; Aguado De Cea, Antonio
    Cemento hormigón : fabricación, investigación y aplicaciones del cemento y del hormigón
    Date of publication: 2014-01-01
    Journal article

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  • Complementary use of inductive test and bending test for the characterization of SFRC

     Liao, Lin; Pialarissi Cavalaro, Sergio Henrique; de la Fuente Antequera, Alberto; Aguado De Cea, Antonio
    Applied mechanics and materials
    Date of publication: 2014
    Journal article

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    Many researches have been conducted in past decades for promoting the application of steel fibre reinforced concrete (SFRC), either conventional or self-compacting. However, the differences of post-crack behaviour and the properties of these two types of concrete remains unclear. The objective of this paper is to analyse such differences in terms of flexural behaviour, fibre orientation and contribution as well as the fibre content. For that, an extensive experimental campaign was carried out. In total 3 mixes of self-compacting and 3 mixes with traditional concrete were produced with the nominal fibre contents of 30kg/m3, 45kg/m3 and 60kg/m3. In each series, specimens were produces and characterized by three point bending test (code EN 14651) and inductive test. The results illustrate how fibre orientation and distribution justify the differences in the mechanical behaviour of the materials and the scatter of the bending test results.

  • Estimation of the modulus of elasticity for sprayed concrete

     Galobardes Reyes, Isaac; Pialarissi Cavalaro, Sergio Henrique; Aguado De Cea, Antonio; Garcia Vicente, Tomas
    Construction & building materials
    Date of publication: 2014-02
    Journal article

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    The modulus of elasticity is a fundamental parameter for the structural design. It has been studied in the literature and several standards include equations to predict its value for conventional concrete. However, the same is not true in the case of sprayed concrete. This special concrete presents singular characteristics due to the spraying process that must be considered in the prediction of this property. The objective of the present work is to perform an analysis of the modulus of elasticity of sprayed concrete. For that, an experimental program about the mechanical properties of the material was executed. Furthermore, the applicability of formulations available in current codes and guidelines to estimate the modulus of elasticity of conventional concrete is assessed. The analysis conducted provides the basis to adapt these formulations, taking into account the specificities of sprayed concrete. Finally, empirical and semi-analytical expressions are proposed and validated using data from real tunnels.

  • Development of a low pH cementitious material to enlarge bioreceptivity

     Manso Blanco, Sandra; Mestres Bea, Gemma; Ginebra Molins, Maria Pau; de Belie, Nele; Segura Pérez, Ignacio; Aguado De Cea, Antonio
    Construction & building materials
    Date of publication: 2014-03-15
    Journal article

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    This paper presents a laboratory investigation into the development of a low-pH cementitious material in order to enlarge bioreceptivity. Two different options were tested; reduction of Ordinary Portland Cement (OPC) pH and assessment of the suitability of another hydraulic binder with lower pH, Magnesium-Phosphate Cement (MPC). Regarding OPC, additions of acidic compounds such as boric acid and oxalic acid were investigated. Furthermore, an in-depth characterization of MPC was carried out to evaluate its suitability as a binder for concrete. For this purpose, physico-chemical as well as mechanical properties were tested. (C) 2014 Elsevier Ltd. All rights reserved.

    This paper presents a laboratory investigation into the development of a low-pH cementitious material in order to enlarge bioreceptivity. Two different options were tested; reduction of Ordinary Portland Cement (OPC) pH and assessment of the suitability of another hydraulic binder with lower pH, Magnesium-Phosphate Cement (MPC). Regarding OPC, additions of acidic compounds such as boric acid and oxalic acid were investigated. Furthermore, an in-depth characterization of MPC was carried out to evaluate its suitability as a binder for concrete. For this purpose, physico-chemical as well as mechanical properties were tested.

  • Bi-layer diaphragm walls: Parametric study of construction processes

     Segura-Castillo, Luís; Josa Garcia-tornel, Alejandro; Aguado De Cea, Antonio
    Engineering structures
    Date of publication: 2014-02-01
    Journal article

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    The bi-layer diaphragm wall is a new type of slurry wall, designed to improve watertightness and to counter leakage problems. These walls consist of two bonded concrete layers: the first, a conventional Reinforced Concrete (RC) diaphragm wall and the second, a sprayed Steel Fibre Reinforced Concrete (SFRC) layer with a waterproof additive. Here, we analyse and quantify the influence of different construction process parameters on the effectiveness of the bi-layer diaphragm wall technique. Thirty numeric simulations were conducted with an uncoupled structure-section analysis, placing special emphasis on the SFRC layer contribution. The results show that, in all cases, the main flexural strength is provided by the RC layer, with a secondary flexural contribution (between 8% and 15%) by the sprayed SFRC layer. Using satisfactory spraying sequences (detailed herein), a reduction in the steel reinforcement of the RC layer can be obtained in every structural configuration and construction sequence, reaching a maximum percentage reduction of 7.0% of the total bending reinforcement. The displacements are almost completely governed by the thickness of the first layer, and a minor reduction (less than 7.3%) is obtained, when the second layer is included. (C) 2013 Elsevier Ltd. All rights reserved.

  • Radiological protection and mechanical properties of concretes with EAF steel slags

     González-Ortega, Martha Alejandra; Segura Pérez, Ignacio; Pialarissi Cavalaro, Sergio Henrique; Toralles-Carnonari, Berenice; Aguado De Cea, Antonio; Andrello, A. C.
    Construction & building materials
    Date of publication: 2014-01-31
    Journal article

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    The main objective of this paper is to evaluate the behavior of concretes with EAF slags with structural responsibility exposed to gamma radiation. Six mixes were designed: four concretes made with EAF slags, one conventional concrete, and one heavyweight concrete with barite aggregates. Tests were performed to assess properties such as occluded air, density, compressive strength, modulus of elasticity and gamma rays attenuation (µ). The mechanical properties of concretes with EAF are similar or higher than the measured for conventional concretes and, in all cases, are significantly higher than the obtained for concretes with barite. Although the attenuation coefficients of the concretes with EAF slags are lower than that of concrete with barite, the differences in terms of the equivalent wall thickness are relatively small. Such results support the use of EAF slags as a structural concrete with radiological protection capability.

    The main objective of this paper is to evaluate the behavior of concretes with EAF slags with structural responsibility exposed to gamma radiation. Six mixes were designed: four concretes made with EAF slags, one conventional concrete, and one heavyweight concrete with barite aggregates. Tests were performed to assess properties such as occluded air, density, compressive strength, modulus of elasticity and gamma rays attenuation (μ). The mechanical properties of concretes with EAF are similar or higher than the measured for conventional concretes and, in all cases, are significantly higher than the obtained for concretes with barite. Although the attenuation coefficients of the concretes with EAF slags are lower than that of concrete with barite, the differences in terms of the equivalent wall thickness are relatively small. Such results support the use of EAF slags as a structural concrete with radiological protection capability.

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    Alternative methodology to consider damage and expansions in external sulfate attack modeling  Open access

     Ikumi Montserrat, Tai; Pialarissi Cavalaro, Sergio Henrique; Segura Pérez, Ignacio; Aguado De Cea, Antonio
    Cement and concrete research
    Date of publication: 2014-09-01
    Journal article

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    A diffusion ¿ reaction numerical model is proposed to simulate the response of concrete exposed to external sulfate attack. Diffusion properties are modified based on the strain reached and the ratio of porosity filled by ettringite. A direct and intuitive approach is proposed for the consideration of the diffusion in a cracked porous media based on the constitutive law of the material. A methodology to compute expansions based on a more realistic consideration of the concrete porosimetry is presented, by which it is possible to distinguish different strain contributions from different pore sizes. The described approach also allows the consideration of different capacities to accommodate expansive product for each pore size considered and the faster filling rate existent in small pores. Critical parameters of the numerical model developed are recognized and established. Expansions obtained by the new model are in good agreement with experimental data published in the literature

    A diffusion–reaction numerical model is proposed to simulate the response of concrete exposed to external sulfate attack. Diffusion properties are modified based on the strain reached and the ratio of porosity filled by ettringite. A direct and intuitive approach is proposed for the consideration of the diffusion in a cracked porous media based on the constitutive law of the material. A methodology to compute expansions based on a more realistic consideration of the concrete porosimetry is presented, by which it is possible to distinguish different strain contributions from different pore sizes. The described approach also allows the consideration of different capacities to accommodate expansive product for each pore size considered and the faster filling rate existent in small pores. Critical parameters of the numerical model developed are recognized and established. Expansions obtained by the new model are in good agreement with experimental data published in the literature

    Postprint (author’s final draft)

  • Fibre distribution in macro-plastic fibre reinforced concrete slab-panels

     Pujadas Alvarez, Pablo; Blanco Álvarez, Ana; Pialarissi Cavalaro, Sergio Henrique; de la Fuente Antequera, Alberto; Aguado De Cea, Antonio
    Construction & building materials
    Date of publication: 2014-08-14
    Journal article

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    This paper focuses on the study of the influence of flowability and wall-effects of the formwork in the orientation pattern of macro-plastic fibres. In order to identify the preferential orientation of fibres caused by the geometry of slabs, pairs of specimens drilled from PFRC slabs with different width/length ¿ ratio are tested using the multidirectional double punch test (MDPT). The results show that plastic fibres tend to be oriented parallel to the walls or surfaces of the formwork and perpendicular to the flow direction for a free surface flow. The side walls slightly redistribute the fibre orientation, as the transverse dimension of the slabs is reduced. Additionally, a computed tomography (CT-scans) was, for the first time, successfully applied to assess the amount of macro-plastic fibres as well as its distribution and orientation in a prismatic core.

    This paper focuses on the study of the influence of flowability and wall-effects of the formwork in the orientation pattern of macro-plastic fibres. In order to identify the preferential orientation of fibres caused by the geometry of slabs, pairs of specimens drilled from PFRC slabs with different width/length – ratio are tested using the multidirectional double punch test (MDPT). The results show that plastic fibres tend to be oriented parallel to the walls or surfaces of the formwork and perpendicular to the flow direction for a free surface flow. The side walls slightly redistribute the fibre orientation, as the transverse dimension of the slabs is reduced. Additionally, a computed tomography (CT-scans) was, for the first time, successfully applied to assess the amount of macro-plastic fibres as well as its distribution and orientation in a prismatic core.

  • Multidirectional double punch test to assess the post-cracking behaviour and fibre orientation of FRC

     Pujadas Alvarez, Pablo; Blanco Álvarez, Ana; Pialarissi Cavalaro, Sergio Henrique; de la Fuente Antequera, Alberto; Aguado De Cea, Antonio
    Construction & building materials
    Date of publication: 2014-05-15
    Journal article

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    The wide variety of tests currently used for the characterization of fibre reinforced concrete (FRC) only allow a unidirectional characterization (without considering the orientation of the fibres in the matrix). However, from a design-oriented perspective, the anisotropy due to the dispersion and orientation of fibres has to be taken into account when characterizing the mechanical behaviour of the material. In this paper, an alternative to the conventional tests applied for the characterization of FRC is proposed. The multidirectional double punch test (MDPT) consists of a double punch test applied to a cubic specimen. Due to the specimen shape in a single procedure an estimation of the fibre orientation efficiency can be obtained, establishing a link between the mechanical properties of FRC with the fibre orientation. Thereby, this paper represents a meaningful contribution to provide a step towards the development of a rational and design-oriented constitutive model for real-scale structures.

    The wide variety of tests currently used for the characterization of fibre reinforced concrete (FRC) only allow a unidirectional characterization (without considering the orientation of the fibres in the matrix). However, from a design-oriented perspective, the anisotropy due to the dispersion and orientation of fibres has to be taken into account when characterizing the mechanical behaviour of the material. In this paper, an alternative to the conventional tests applied for the characterization of FRC is proposed. The multidirectional double punch test (MDPT) consists of a double punch test applied to a cubic specimen. Due to the specimen shape in a single procedure an estimation of the fibre orientation efficiency can be obtained, establishing a link between the mechanical properties of FRC with the fibre orientation. Thereby, this paper represents a meaningful contribution to provide a step towards the development of a rational and design-oriented constitutive model for real-scale structures.

  • Rehabilitación de forjados de la Casa Museo Gaudí en el Parque Güell

     Coll, Jordi; Altet, Jordi; Aguado De Cea, Antonio
    Date of publication: 2014-04-01
    Book chapter

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    Congreso Latinoamericano sobre "Patología de la construcción, tecnológía de la rehabilitación y gestión del patrimonio"

    La casa Museo Gaudí es un edificio con la máxima catalogación de Patrimonio de la Generalitat dentro del Parque Güell de Barcelona, conjunto protegido como patrimonio de la humanidad por la UNESCO. Recientemente, dentro de un conjunto más amplio de actuaciones, se ha realizado la rehabilitación de los forjados de la citada estructura, formado por viguetas de madera y metálicas y revoltón de cerámica en arco entre las viguetas con el consiguiente relleno posterior. Entre los condicionantes de la rehabilitación, aparte de los habituales de este tipo de estructuras, se añadía un tema de plazos y la necesidad de dar monolitismo y aumentar rigidez al conjunto, ya que en la situación anterior, implicaba una limitación del número de visitantes. Como alternativa se ha propuesto y ejecutado un hormigón ligero autocompactante con fibras, lo cual en la combinación de todos estos requerimientos implica el desarrollo de una obra pionera, dentro de la información que la que se dispone. El objetivo de la comunicación, aparte de presentar las características de estos hormigones, es mostrar los procedimientos constructivos en los que se ha realizado la rehabilitación, reflejando los elementos de conexión, y la forma de garantizar el trabajo conjunto.

  • Complementary use of inductive test and bending test for the characterization of SFRC

     Liao, Lin; Pialarissi Cavalaro, Sergio Henrique; de la Fuente Antequera, Alberto; Aguado De Cea, Antonio
    Date of publication: 2014-07-01
    Book chapter

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    Selected, peer reviewed papers from the 4th International Conference on Civil Engineering, Architechture and Building Materials (CEABM 2014), May 24-25, 2014, Haikou, China.

    Many researches have been conducted in past decades for promoting the application of steel fibre reinforced concrete (SFRC), either conventional or self-compacting. However, the differences of post-crack behaviour and the properties of these two types of concrete remains unclear. The objective of this paper is to analyse such differences in terms of flexural behaviour, fibre orientation and contribution as well as the fibre content. For that, an extensive experimental campaign was carried out. In total 3 mixes of self-compacting and 3 mixes with traditional concrete were produced with the nominal fibre contents of 30kg/m3, 45kg/m3 and 60kg/m3. In each series, specimens were produces and characterized by three point bending test (code EN 14651) and inductive test. The results illustrate how fibre orientation and distribution justify the differences in the mechanical behaviour of the materials and the scatter of the bending test results.

  • Correlación entre TCOD y desplazamiento axial en el ensayo Barcelona

     Pujadas Alvarez, Pablo; Blanco Álvarez, Ana; Pialarissi Cavalaro, Sergio Henrique; de la Fuente Antequera, Alberto; Aguado De Cea, Antonio
    Congreso de la Asociación Científico-Técnica del Hormigón Estructural
    Presentation's date: 2014-06-04
    Presentation of work at congresses

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    La necesidad de medir el desplazamiento circunferencial (total circumferential opening displacemento TCOD ) en el ensayo Barcelona implica el uso de un caro extensómetro circunferencial. El modelo desarrollado en la presente comunicación permite una positiva simplificación elimina la necesidad de utilizar la cadena extensométrica mediante la estimación directa del TCOD a partir del desplazamiento axial (d). Además las ecuaciones desarrolladas en este artículo proporcionan una clara comprensión de los mecanismos físicos que gobiernan el ensayo Barcelona. La comparación con los valores experimentales indica que el m odelo es capaz de predecir con un buen ajuste la curva entera carga-TCOD, independientemente del tipo de hormigón (convencional HRF o alta resistencia UHPFRC), del tipo de fibra (acero o plásticas, micro o macro) y el comportamiento postfisuración (hardening o softening).

    La necesidad de medir el desplazamiento circunferencial (total circumferential opening displacemento TCOD ) en el ensayo Barcelona implica el uso de un caro extensómetro circunferencial. El modelo desarrollado en la presente comunicación permite una positiva simplificación elimina la necesidad de utilizar la cadena extensométrica mediante la estimación directa del TCOD a partir del desplazamiento axial (δ). Además las ecuaciones desarrolladas en este artículo proporcionan una clara comprensión de los mecanismos físicos que gobiernan el ensayo Barcelona. La comparación con los valores experimentales indica que el m odelo es capaz de predecir con un buen ajuste la curva entera carga-TCOD, independientemente del tipo de hormigón (convencional HRF o alta resistencia UHPFRC), del tipo de fibra (acero o plásticas, micro o macro) y el comportamiento postfisuración (hardening o softening).

  • Comportamiento a flexión de losas de hormigón reforzado con fibras (HRF)

     Blanco Álvarez, Ana; Pujadas Alvarez, Pablo; de la Fuente Antequera, Alberto; Pialarissi Cavalaro, Sergio Henrique; Aguado De Cea, Antonio
    Congreso de la Asociación Científico-Técnica del Hormigón Estructural
    Presentation's date: 2014-06-05
    Presentation of work at congresses

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  • Fibre reinforced precast concrete segments: design and applications

     de la Fuente Antequera, Alberto; LIAO, LIN; Pialarissi Cavalaro, Sergio Henrique; Aguado De Cea, Antonio
    ITA-AITES World Tunnel Congress
    Presentation's date: 2014-05-14
    Presentation of work at congresses

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    The use of structural fibre as replacement of the traditional reinforcement in precast concrete segmental linings is a widespread practice. As a matter of fact, more than forty examples of application in tunnels and vertical shafts can be cited. The success of using fibres in this structural elements lies in the mechanical improvements (reduction of the crack width, increasing of the toughness, among others) as well as in economic reasons (reduction of the labour force as well as of the production periods, increasing the efficiency, among others) that could be achieved. In this sense, the main goals of this scientific contribution consist of, on the one hand, presenting and analysing some of the more relevant applications of fibre reinforced precast concrete segmental linings existing up to date and, on the other hand, presenting a numeral strategy to optimize the reinforcement in this sort of elements as well as its application to recent real examples already constructed or under construction in the metropolitan area of Barcelona.

    The use of structural fibre as replacement of the traditional reinforcement in precast concrete segmental linings is a widespread practice. As a matter of fact, more than forty examples of application in tunnels and vertical shafts can be cited. The success of using fibres in this structural elements lies in the mechanical improvements (reduction of the crack width, increasing of the toughness, among others) as well as in economic reasons (reduction of the labour force as well as of the production periods, increasing the efficiency, among others) that could be achieved. In this sense, the main goals of this scientific contribution consist of, on the one hand, presenting and analysing some of the more relevant applications of fibre reinforced precast concrete segmental linings existing up to date and, on the other hand, presenting a numeral strategy to optimize the reinforcement in this sort of elements as well as its application to recent real examples already constructed or under construction in the metropolitan area of Barcelona.

  • Dovelas de hormigón prefabricado reforzado con fibras para el soporte de túneles y pozos verticales

     de la Fuente Antequera, Alberto; Blanco Álvarez, Ana; Pujadas Alvarez, Pablo; Aguado De Cea, Antonio
    Congreso de la Asociación Científico-Técnica del Hormigón Estructural
    Presentation's date: 2014-06-04
    Presentation of work at congresses

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  • Degradación acelerada de estructuras de hormigón armado prefabricado en medios marinos agresivos

     Segura Pérez, Ignacio; Pialarissi Cavalaro, Sergio Henrique; de la Fuente Antequera, Alberto; Aguado De Cea, Antonio; Alegre Heitzmann, Vicente
    Congreso de la Asociación Científico-Técnica del Hormigón Estructural
    Presentation's date: 2014-06-05
    Presentation of work at congresses

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  • Módulo de hormigón prefabricado reforzado con fibras plásticas estructurales

     de la Fuente Antequera, Alberto; Pialarissi Cavalaro, Sergio Henrique; Aguado De Cea, Antonio
    Date: 2014-03-10
    Report

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  • Especificaciones del producto y del servicio a desarrollar (BAHORIS)

     Aguado De Cea, Antonio; de la Fuente Antequera, Alberto
    Date: 2014-01-24
    Report

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  • Definición del aditivo superfluidificante para hormigón autocompactante destinado a la ejecución de dovelas

     Aguado De Cea, Antonio; Pialarissi Cavalaro, Sergio Henrique; de la Fuente Antequera, Alberto; Segura, Ignacio
    Date: 2014-05-19
    Report

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  • Parámetros influyentes en el comportamiento resistente de dovelas

     Aguado De Cea, Antonio; Pialarissi Cavalaro, Sergio Henrique; de la Fuente Antequera, Alberto
    Date: 2014-05-19
    Report

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  • Simulación previa de los ensayos con modelos de elementos finitos

     Aguado De Cea, Antonio; Pialarissi Cavalaro, Sergio Henrique; de la Fuente Antequera, Alberto; Segura, Ignacio
    Date: 2014-05-19
    Report

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  • FIBHAC: Fibras y hormigón autocompactante. Desarrollo de un nuevo concepto de dovela prefabricada para túneles

     Pialarissi Cavalaro, Sergio Henrique; Torrents Dolz, Josep Maria; de la Fuente Antequera, Alberto; Aguado De Cea, Antonio
    Participation in a competitive project

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  • Caracterización mecánica de los testigos extraídos de los bataches

     Aguado De Cea, Antonio; Pialarissi Cavalaro, Sergio Henrique; de la Fuente Antequera, Alberto
    Date: 2014-01-13
    Report

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  • Ensayos destructivos y no destructivos del hormigón reforzado con fibras (parte 1)

     Aguado De Cea, Antonio; Pialarissi Cavalaro, Sergio Henrique; de la Fuente Antequera, Alberto; Segura, Ignacio
    Date: 2014-05-23
    Report

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  • Evaluación de la reducción o eliminación del curado a vapor

     Aguado De Cea, Antonio; Pialarissi Cavalaro, Sergio Henrique; de la Fuente Antequera, Alberto
    Date: 2014-05-19
    Report

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  • Ensayos destructivos y no destructivos del hormigón reforzado con fibras (parte 2)

     Aguado De Cea, Antonio; Pialarissi Cavalaro, Sergio Henrique; de la Fuente Antequera, Alberto
    Date: 2014-05-19
    Report

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  • Propuesta de optimización del refuerzo de las dovelas prefabricadas del pozo de Montcada empleando HRF

     de la Fuente Antequera, Alberto; Pialarissi Cavalaro, Sergio Henrique; Aguado De Cea, Antonio
    Date: 2014-05-19
    Report

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  • Bioreceptivity optimisation of concrete substratum to stimulate biological colonisation  Open access

     Manso Blanco, Sandra
    Defense's date: 2014-05-09
    Universitat Politècnica de Catalunya
    Theses

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    La ausencia de espacios verdes en las ciudades es consecuencia del constante incremento poblacional y el proceso de urbanización. Sin embargo, existe un interés social creciente en aumentarlos desde inicios del siglo XX. Los beneficios asociados pueden englobarse en tres niveles: social, económico y ecológico. Por ello, la incorporación de elementos vegetales en los edificios se ha visto, principalmente, como una alternativa en aquellas ciudades con escasez de espacios disponibles para la construcción de áreas verdes. En este sentido, diversos sistemas han sido desarrollados tanto a nivel de fachadas como de cubiertas vegetales. Desafortunadamente, los sistemas existentes presentan diversos inconvenientes, los cuales se refieren a los costes de instalación y mantenimiento, a la baja integración entre los elementos naturales y la estructura, la carga adicional que conlleva y, en algunos casos, la limitación en su uso, entre otros.El objetivo general de la presente tesis es demostrar que es posible utilizar el propio material cementicio como soporte biológico, para lo cual se han considerado dos líneas principales: modificar de forma controlada el material cementicio en base a sus propiedades químicas y físicas y, evaluar la bioreceptividad del soporte en muestras colonizadas.En lo referente al material, primero se abordaron las propiedades químicas, fijándose como prioritario reducir el pH, para lo cual se abordaron dos vías: incorporación de ácidos en morteros en base a cemento Portland y, empleo de cementos en base a fosfato de magnesio. Las reducciones de pH alcanzadas para el cemento Portland no fueron significativas y sí, en cambio, la afectación a nivel de resistencias fue elevada. Por contra, los resultados obtenidos para el cemento en base a fosfato de magnesio fueron positivos, sin efectos secundarios.Respecto a las propiedades físicas, se han considerado la porosidad y la rugosidad. Para la modificación controlada de estas propiedades se realizaron cambios entre dosificaciones en cuanto al tipo de cemento, al esqueleto granular, a la relación agua-cemento y a la cantidad de pasta de cemento. La metodología usada para la estimación de la cantidad de pasta de cemento funcionó correctamente para el mortero de cemento Portland. Sin embargo, el mortero en base a cemento de fosfato de magnesio presentó particularidades que hicieron cambiar los criterios de selección. Veintitrés tipos de mortero de diferente bioreceptividad fueron caracterizados y los resultados obtenidos permitieron reducir dicho número a seis, los cuales fueron expuestos a colonización.En el proceso de evaluación del crecimiento biológico, las muestras fueron expuestas tanto a condiciones controladas de laboratorio, mediante un ensayo acelerado, como a condiciones ambientales, habiéndose obtenido los mejores resultados para las muestras en base al cemento de fosfato de magnesio.Finalmente, las muestras fueron expuestas a colonización ambiental, ya que los resultados podrían diferir considerablemente. Además de evaluarse los diferentes grados de bioreceptividad de las muestras entre sí, también se evaluó la influencia de la inclinación (horizontal y vertical) así como de la localización comparando tres emplazamientos (Barcelona ciudad, parque natural del Montseny y Gante ciudad). Diferencias significativas fueron observadas entre muestras con diferente inclinación así como entre las localizaciones con diferente grado de contaminación ambiental. Las muestras horizontales presentaron mejores resultados a nivel de diversidad y cuantificación. Y, además, las muestras colocadas en zonas urbanas obtuvieron mejores resultados que aquellas en emplazadas en una zona no contaminada. Sin embargo, los resultados muestran la necesidad de más investigación en condiciones ambientales así como por periodos más prolongados.

    Cotutela Universitat Politècnica de Catalunya i Ghent University

    The lack of green areas in cities is caused by the increase in population and the urbanisation process. However, an increasing interest in city greenery was observed since the beginning of twentieth century. Several benefits are associated with green areas from a social, economic and ecologic point of view. Consequently, the solution to increase the urban green spaces lies in their inclusion on structures¿ surfaces. In that sense, a number of different technologies were developed which can be grouped into green walls and green roofs. Unfortunately, existing systems for both green walls and green roofs present several disadvantages in terms of installation and maintenance costs, low level of integration with the structure, extra loads, limitations in their use in rehabilitation projects, and others. The general objective of this dissertation is to provide a first approach to the possibility of using a structure surface as biological substratum. This was treated considering two different research lines. The first research line includes the modification of the chemical and physical properties of the cementitious material, which will be used as substratum. Then, the second issue is the evaluation of materials¿ bioreceptivity under both laboratory and environmental conditions. Regarding the material, chemical properties were firstly studied. pH was taken as a priority from the diversity of involved chemical properties. In that sense, two different ways to obtain a low pH cementitious material were studied. First, it was attempted to reduce the pH of the most common hydraulic binder, Ordinary Portland Cement (OPC). Then, the characterisation of Magnesium Phosphate Cement (MPC) as a hydraulic binder of naturally low pH was carried out. Insufficient reduction in the pH of OPC was obtained and properties such as flexural and compressive strength were highly affected. In contrast, positive results were obtained regarding the use of MPC as hydraulic binder for the specific purpose to be used as a biological substratum. Regarding the physical properties, porosity and roughness were the main properties considered. For that purpose, modifications were made to the composition of different samples, by means of modifying the hydraulic binder, granular skeleton, the water to cement ratio and the amount of cement paste. The methodology used for the estimation of the optimal cement paste content worked well for OPC specimens although MPC responded differently. The characterisation of the twenty-three initial materials¿ bioreceptivities provided significantly different results. Consequently, six different mix designs were selected to be exposed to colonisation. Afterwards, the evaluation of the materials¿ bioreceptivity in terms of colonisation was studied under both laboratory and environmental conditions. Regarding the experimental program under laboratory conditions, an accelerated laboratory test was carried out to evaluate the behavior of different specimens when they were exposed to colonization. Magnesium Phosphate Cement specimens obtained better results than OPC mortars for algal colonisation under those particular conditions. Finally, specimens were also evaluated under environmental conditions, since these may significantly differ from laboratory conditions. Furthermore, two different inclinations and three different locations were studied. Significant differences were observed between inclinations (horizontal and vertical) and between locations with different contamination levels (Barcelona city, Natural Park of Montseny and Ghent city). Better results were obtained with horizontal specimens in terms of predominant genus diversity as well as quantitative level of colonisation. Moreover, specimens located in urban areas (Barcelona city) showed also better results. However, the environmental experimental programs should be continued over a longer time span to reach more conclusive results.

    La ausencia de espacios verdes en las ciudades es consecuencia del constante incremento poblacional y el proceso de urbanización. Sin embargo, existe un interés social creciente en aumentarlos desde inicios del siglo XX. Los beneficios asociados pueden englobarse en tres niveles: social, económico y ecológico. Por ello, la incorporación de elementos vegetales en los edificios se ha visto, principalmente, como una alternativa en aquellas ciudades con escasez de espacios disponibles para la construcción de áreas verdes. En este sentido, diversos sistemas han sido desarrollados tanto a nivel de fachadas como de cubiertas vegetales. Desafortunadamente, los sistemas existentes presentan diversos inconvenientes, los cuales se refieren a los costes de instalación y mantenimiento, a la baja integración entre los elementos naturales y la estructura, la carga adicional que conlleva y, en algunos casos, la limitación en su uso, entre otros. El objetivo general de la presente tesis es demostrar que es posible utilizar el propio material cementicio como soporte biológico, para lo cual se han considerado dos líneas principales: modificar de forma controlada el material cementicio en base a sus propiedades químicas y físicas y, evaluar la bioreceptividad del soporte en muestras colonizadas. En lo referente al material, primero se abordaron las propiedades químicas, fijándose como prioritario reducir el pH, para lo cual se abordaron dos vías: incorporación de ácidos en morteros en base a cemento Portland y, empleo de cementos en base a fosfato de magnesio. Las reducciones de pH alcanzadas para el cemento Portland no fueron significativas y sí, en cambio, la afectación a nivel de resistencias fue elevada. Por contra, los resultados obtenidos para el cemento en base a fosfato de magnesio fueron positivos, sin efectos secundarios. Respecto a las propiedades físicas, se han considerado la porosidad y la rugosidad. Para la modificación controlada de estas propiedades se realizaron cambios entre dosificaciones en cuanto al tipo de cemento, al esqueleto granular, a la relación agua-cemento y a la cantidad de pasta de cemento. La metodología usada para la estimación de la cantidad de pasta de cemento funcionó correctamente para el mortero de cemento Portland. Sin embargo, el mortero en base a cemento de fosfato de magnesio presentó particularidades que hicieron cambiar los criterios de selección. Veintitrés tipos de mortero de diferente bioreceptividad fueron caracterizados y los resultados obtenidos permitieron reducir dicho número a seis, los cuales fueron expuestos a colonización. En el proceso de evaluación del crecimiento biológico, las muestras fueron expuestas tanto a condiciones controladas de laboratorio, mediante un ensayo acelerado, como a condiciones ambientales, habiéndose obtenido los mejores resultados para las muestras en base al cemento de fosfato de magnesio. Finalmente, las muestras fueron expuestas a colonización ambiental, ya que los resultados podrían diferir considerablemente. Además de evaluarse los diferentes grados de bioreceptividad de las muestras entre sí, también se evaluó la influencia de la inclinación (horizontal y vertical) así como de la localización comparando tres emplazamientos (Barcelona ciudad, parque natural del Montseny y Gante ciudad). Diferencias significativas fueron observadas entre muestras con diferente inclinación así como entre las localizaciones con diferente grado de contaminación ambiental. Las muestras horizontales presentaron mejores resultados a nivel de diversidad y cuantificación. Y, además, las muestras colocadas en zonas urbanas obtuvieron mejores resultados que aquellas en emplazadas en una zona no contaminada. Sin embargo, los resultados muestran la necesidad de más investigación en condiciones ambientales así como por periodos más prolongados

  • Desenvolupament de models numèrics per el disseny i anàlisi de ferms rígids, semi-rígids i flexibles

     de la Fuente Antequera, Alberto; Aguado De Cea, Antonio
    Participation in a competitive project

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  • Desarrollo de mejores rehabilitaciones locales en infraestructuras (MERLIN)

     Pialarissi Cavalaro, Sergio Henrique; Blanco Álvarez, Ana; de la Fuente Antequera, Alberto; Aguado De Cea, Antonio
    Participation in a competitive project

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  • Characterization of the properties of steel fiber reinforced concrete by means of the generalized Barcelona test

     Carmona Malatesta, Sergio; Aguado De Cea, Antonio; Molins Borrell, Climent
    Construction & building materials
    Date of publication: 2013-11
    Journal article

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  • Access to the full text
    Ensayo de doble punzonamiento para concreto reforzado con fibra: efecto del tamaño y origen de la probeta  Open access

     Aire, Carlos; Molins Borrell, Climent; Aguado De Cea, Antonio
    Concreto y cemento: investigación y desarrollo
    Date of publication: 2013
    Journal article

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    Traditionally, to characterize the behavior of reinforced concrete with fiber (CRF) flexural tests are performed on beams. However, in accordance with various studies on FRC, it has been seen different variation coefficients of the order of 20 % for the results of flexural test beams. Recently, it has been developed a new method based on the double punching, called Barcelona test, as an alternative to determine the resistance to the indirect traction of the FRC. It is a test of easy execution over which a cylinder of 150 mm of diameter and 150 mm of height, undergoes double punching test, which allows to obtain the resistance to indirect tension of the FRC, with coefficients of variation less than those obtained by methods which employ beams. This article shows the results of a comparative study between results of resistance and toughness applying the Barcelona test obtained in molded test cylinders of 100 and 150 mm and cores of 93 and 153 mm.

    Traditionally, to characterize the behavior of reinforced concrete with fiber (CRF) flexural tests are performed on beams. However, in accordance with various studies on FRC, it has been seen different variation coefficients of the order of 20 % for the results of flexural test beams. Recently, it has been developed a new method based on the double punching, called Barcelona test, as an alternative to determine the resistance to the indirect traction of the FRC. It is a test of easy execution over which a cylinder of 150 mm of diameter and 150 mm of height, undergoes double punching test, which allows to obtain the resistance to indirect tension of the FRC, with coefficients of variation less than those obtained by methods which employ beams. This article shows the results of a comparative study between results of resistance and toughness applying the Barcelona test obtained in molded test cylinders of 100 and 150 mm and cores of 93 and 153 mm.

  • Bi-layer diaphragm walls: experimental and numerical structural analysis

     Segura-Castillo, Luís; Aguado De Cea, Antonio; Josa Garcia-tornel, Alejandro
    Engineering structures
    Date of publication: 2013-11
    Journal article

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    The bi-layer diaphragm wall, a new type of wall, consists of two concrete layers, the first of which is poured and the second sprayed, in different construction stages. A major aim of the research conducted is to maximize the functional attributes of the second layer, enhancing both structural performance and watertightness. The central objective of this study is to corroborate the structural behaviour of these walls in experimental and numerical terms. It follows a three-step methodology: a full-scale experimental campaign; development of a Finite Element Model (FEM) capable of predicting the structural behaviour of the wall; and, assessment of the second layer contribution. The experimental campaign confirmed the viability of the constructive solution and the FEM model accurately reflected the experimental data. A comparison between the bi-layer wall and other single-layer walls showed that the contribution of the second layer permitted reductions in first-layer reinforcement, adding to its various other functional advantages.

  • Design of macro-synthetic fibre reinforced concrete pipes

     de la Fuente Antequera, Alberto; Campos Escariz, Renata; Domingues de Figueiredo, Antonio; Aguado De Cea, Antonio
    Construction & building materials
    Date of publication: 2013-06-03
    Journal article

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    This paper presents an experimental campaign in which concrete pipes were manufactured using plastic fibres as the sole reinforcement material. In this regard, it has been demonstrated that the use of plastic fibres is compatible with pipe production systems, and that, when subjected to the crushing test (CT), plastic fibre reinforced pipes yield strength classes that are attractive in terms of the growth of this material in the concrete pipe industry. Moreover, the results obtained from both the characterisation of the material and the mechanical behaviour of the pipes have been used to verify that the Model for the Analysis of Pipes (MAPs) is an appropriate tool for the design of such pipes. Finally, this paper presents a direct design methodology which was used to establish the firsts design tables for fibre reinforced concrete pipes presented in the scientific literature. This methodology can be used to estimate the strength requirements of the fibre reinforced concrete needed to reach the strength classes set out in EN 1916:2002, without having to resort to the CT as an indirect design method.

    This paper presents an experimental campaign in which concrete pipes were manufactured using plastic fibres as the sole reinforcement material. In this regard, it has been demonstrated that the use of plastic fibres is compatible with pipe production systems, and that, when subjected to the crushing test (CT), plastic fibre reinforced pipes yield strength classes that are attractive in terms of the growth of this material in the concrete pipe industry. Moreover, the results obtained from both the characterisation of the material and the mechanical behaviour of the pipes have been used to verify that the Model for the Analysis of Pipes (MAPs) is an appropriate tool for the design of such pipes. Finally, this paper presents a direct design methodology which was used to establish the firsts design tables for fibre reinforced concrete pipes presented in the scientific literature. This methodology can be used to estimate the strength requirements of the fibre reinforced concrete needed to reach the strength classes set out in EN 1916:2002, without having to resort to the CT as an indirect design method.

  • Estudio experimental y analítico sobre el comportamiento a compresión de paneles sandwich ligeros con EPS

     Carbonari, Gilberto; Pialarissi Cavalaro, Sergio Henrique; Cansario Pérez, María del Mar; Aguado De Cea, Antonio
    Materiales de construcción (Madrid)
    Date of publication: 2013-07
    Journal article

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    This study presents a detailed characterization of the behavior of EPS sandwich panels subject to normal load taking into account several variables. For that, two experimental programs were performed, leading to the proposal of an analytical formulation to estimate the maximum load resisted. The results obtained show how the height of the panel, the material properties, the position and configuration of the reinforcement may affect the resistance of panels. Special attention should be given to the eccentric position of the reinforcement, which may reduce considerably the maximum load resisted. Some recommendations about the optimum placement of the reinforcement are proposed.

  • Gaudi and reinforced concrete in construction

     Grima Lopez, Rosa Maria; Aguado De Cea, Antonio; Gomez Serrano, Jose
    International journal of architectural heritage
    Date of publication: 2013
    Journal article

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    The first two decades of the 20th century witnessed the introduction and expansion of reinforced concrete as a building material in Spain. Few years passed between the introduction of the first patents in the most industrialized areas of the Iberian Peninsula and the subsequent generalization of the technique through scientific knowledge obtained in universities. This period coincides almost completely with the professional career of Antoni Gaudí, one of the most famous Catalan architects. This study reports that Gaudí had contact with this new material and discusses the transition he made from the traditional construction methods to the use of reinforced concrete in his later works. Placing the starting point in the relationship between Antonio Gaudí and the industrialists who built the first cement factories in Catalonia (especially Eusebi Güell), the research on the patents to which he had access are presented and the characteristics of his works with reinforced structures and materials are described.

    The first two decades of the 20th century witnessed the introduction and expansion of reinforced concrete as a building material in Spain. Few years passed between the introduction of the first patents in the most industrialized areas of the Iberian Peninsula and the subsequent generalization of the technique through scientific knowledge obtained in universities. This period coincides almost completely with the professional career of Antoni Gaudí, one of the most famous Catalan architects. This study reports that Gaudí had contact with this new material and discusses the transition he made from the traditional construction methods to the use of reinforced concrete in his later works. Placing the starting point in the relationship between Antonio Gaudí and the industrialists who built the first cement factories in Catalonia (especially Eusebi Güell), the research on the patents to which he had access are presented and the characteristics of his works with reinforced structures and materials are described.

  • New unreacted-core model to predict pyrrhotite oxidation in concrete dams

     Oliveira da Silva, Izelman; Pialarissi Cavalaro, Sergio Henrique; Aguado De Cea, Antonio
    Journal of materials in civil engineering
    Date of publication: 2013-03
    Journal article

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    Pyrites and pyrrhotites are the most abundant minerals of the iron sulfide group in nature and may be found in the aggregates used to produce concrete. In the presence of water and oxygen, such compounds generate expansive reactions that may have severe structural damages. This is especially critical in concrete dams, given the large volume of material used and the restrictions in movement imposed by the surroundings. In these cases, the definition of adequate rehabilitation programs depends on the prediction of the expansive reaction evolution and the future behavior of the structure. Although models that describe solid particle¿gas reactions may be used with this purpose, none were specifically developed to simulate this phenomenon in dams. This paper introduces a new kinetic model based on the unreacted-core model for pyrrhotite oxidation. The comparison of the results obtained with this new model and with the direct application of the unreacted-core model show significant differences. Following an extensive parametric study, a simplified constitutive equation is proposed to estimate the pyrrhotite oxidation kinetics in concrete dams. The estimations performed with this constitutive equation agree with the experimental data obtained in the tests of different particle sizes.

  • New kinetic model to quantify the internal sulfate attack in concrete

     Oliveira, Izelman; Pialarissi Cavalaro, Sergio Henrique; Aguado De Cea, Antonio
    Cement and concrete research
    Date of publication: 2013-01
    Journal article

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  • Application of constitutive models in European codes to RC-FRC

     Blanco Álvarez, Ana; Pujadas Alvarez, Pablo; de la Fuente Antequera, Alberto; Pialarissi Cavalaro, Sergio Henrique; Aguado De Cea, Antonio
    Construction & building materials
    Date of publication: 2013-03
    Journal article

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    The recent publication of codes for the design of FRC is a major step towards extending the use of the material. An in depth analysis indicates several differences between the constitutive models proposed in the existing codes. In this study, these models are compared and a numerical simulation is performed to evaluate their differences in terms of the structural behavior predicted and measured in an experimental program of RC-FRC elements. The predictions provided by the models fit satisfactorily the experimental results for elements with steel fibers and with plastic fibers

  • Caracterización mecánica de hormigones con alto contenido en finos

     Sáez, Carla; Aguado De Cea, Antonio
    Cemento hormigón : fabricación, investigación y aplicaciones del cemento y del hormigón
    Date of publication: 2013-03
    Journal article

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  • Caracterización de los morteros de relleno usados en diferentes túneles españoles

     Pialarissi Cavalaro, Sergio Henrique; Aguado De Cea, Antonio
    Materiales de construcción (Madrid)
    Date of publication: 2013-01-01
    Journal article

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    El objetivo principal del presente estudio es llevar a cabo la comparación de las dosificaciones de mortero de relleno empleadas en algunos de los grandes túneles españoles para rellenar el hueco anular dejado entre el terreno y el extradós de las dovelas. Inicialmente se hace una nueva propuesta experimental usando la composición y los materiales correspondientes a 6 dosificaciones usadas en 4 túneles. Los resultados obtenidos indican diferencias significativas en cuanto a la densidad, a la consistencia y a las propiedades reológicas. De acuerdo con las estimaciones realizadas, ello se traduce en diferencias de hasta un 67% en la potencia requerida del sistema de bombas de la tuneladora para inyectar el material. Por otro lado, se refleja una correlación entre el contenido de finos de la mezcla y las propiedades reológicas. Esa correlación puede servir para controlar y modificar dichas propiedades de manera fácil y rápida a pie de obra.

  • New analytical model to generalize the Barcelona Test using axial displacement

     Pujadas Alvarez, Pablo; Blanco Álvarez, Ana; Pialarissi Cavalaro, Sergio Henrique; de la Fuente Antequera, Alberto; Aguado De Cea, Antonio
    Journal of civil engineering and management (Spausdinta)
    Date of publication: 2013
    Journal article

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    The Barcelona Test has proved to be very suitable for the systematic control of the tensile properties of Fibre Reinforced Concrete (FRC). Nevertheless, the need to measure the total circumferential opening displacement (TCOD) of the specimen entails the use of an expensive circumferential extensometer. In order to simplify the test, studies from the literature propose the use of the axial displacement of the press (d) instead of the TCOD, obtaining empirical equations to correlate the energy estimated with both measurements. However, these equations are only valid for d ranging from 1 to 4 mm and were adjusted based on the test results of just a few types of FRC. The verification of this formulation for other types of FRC shows an average error of 51.1%, thus limiting the simplification proposed for the test. In this paper, a new analytical model to convert the d into the TCOD is developed and validated for a wide range of FRC. Besides being applicable to the whole range of d, the new model provides a clear physical understanding of the main mechanism observed during the test and shows an average error of only 6.7%, making it possible to simplify the Barcelona test.

    The Barcelona Test has proved to be very suitable for the systematic control of the tensile properties of Fibre Reinforced Concrete (FRC). Nevertheless, the need to measure the total circumferential opening displacement (TCOD) of the specimen entails the use of an expensive circumferential extensometer. In order to simplify the test, studies from the literature propose the use of the axial displacement of the press (δ) instead of the TCOD, obtaining empirical equations to correlate the energy estimated with both measurements. However, these equations are only valid for δ ranging from 1 to 4 mm and were adjusted based on the test results of just a few types of FRC. The verification of this formulation for other types of FRC shows an average error of 51.1%, thus limiting the simplification proposed for the test. In this paper, a new analytical model to convert the δ into the TCOD is developed and validated for a wide range of FRC. Besides being applicable to the whole range of δ, the new model provides a clear physical understanding of the main mechanism observed during the test and shows an average error of only 6.7%, making it possible to simplify the Barcelona test.

  • Concrete dams with expansive reactions: the diagnosis process

     Río, J.F.; Conesa, F.J.; Chacón, M.; Pardo Bosch, Francesc; Aguado De Cea, Antonio
    ICOLD European Club Symposium
    Presentation's date: 2013-04-10
    Presentation of work at congresses

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    In several concrete dams (around 20 in Spain, according to a recent database of GECOLD) have been detected expansions due mainly to alkali-aggregate reactions (AAR) and internal sulphatic reactions (ISR). The study of expansive behaviour in this structures and its associated facilities include different actions that influence in a transverse mode on aspects which comprise the reactive processes (microsturcture), on materials and the component phases of concrete (mesostructure), and finally, the determination of the effects that are produced in the structural level of the dam (macroscale), the structural typology and the Dam operation mode. In addition, the consequences derived from the concrete expansion can impact both the safety conditions of the dam as the functionality of it, or its related components. Among the effects of these expansions there is the typical cracking pattern, the remaining movements of alignments and levelings, as well as in some cases structural cracks, result of several factors. This communication is intended to illustrate the signs that may appear in a concrete dam with expansions, mainly by ISR, a reaction not overly worked so far. In order to be illustrative, the text will present some particular cases of the Catalan Pyrenees dams with this pathology and will justify the diagnosis established using an own working methodology which is associated at different studies to develop.

  • Multi-criterial integrated analysis system for decision making between different highway's pavements

     Ainchil Lavin, Javier; Aguado De Cea, Antonio
    IRF World Meeting
    Presentation's date: 2013-11-09
    Presentation of work at congresses

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    When taking decisions between different options regarding a section of pavement of a highway several approaches can be used. For decades the classical approach was focused strictly in economics. Initially the cost of construction was only considered, but it was finally replaced by the overall cost of construction and exploitation and maintenance, corrected or not by financials factors that try to quantify the effects of distribution of investment along the time. Lately at the end of XX century the environmental approach started to be developed, taking into account several impacts as consumption of energy, water and raw materials, emissions to atmosphere and waste generation, between others. Questions about how to consider impacts on people related to comfort, noise, safety and perceptions among others were also included in what was called the social aspects of sustainability, a new paradigm that integrates these three dimensions (social, environmental, economics). Accordingly a large number of studies have been made in order to compare different solutions of pavements in terms of these dimensions. While in construction and building several standard methods of comparison have been proposed, ranging from scoring to labeling systems, public works and particularly pavements remain as a field where more improvements are expected. A new integrated method of evaluation is therefore being applied to pavements, defining requirements, criteria and indicators that are being treated in order to establish the value function by means of multi-criteria analysis.

    When taking decisions between different options regarding a section of pavement of a highway several approaches can be used. For decades the classical approach was focused strictly in economics. Initially the cost of construction was only considered, but it was finally replaced by the overall cost of construction and exploitation and maintenance, corrected or not by financials factors that try to quantify the effects of distribution of investment along the time. Lately at the end of XX century the environmental approach started to be developed, taking into account several impacts as consumption of energy, water and raw materials, emissions to atmosphere and waste generation, between others. Questions about how to consider impacts on people related to comfort, noise, safety and perceptions among others were also included in what was called the social aspects of sustainability, a new paradigm that integrates these three dimensions (social, environmental, economics). Accordingly a large number of studies have been made in order to compare different solutions of pavements in terms of these dimensions. While in construction and building several standard methods of comparison have been proposed, ranging from scoring to labeling systems, public works and particularly pavements remain as a field where more improvements are expected. A new integrated method of evaluation is therefore being applied to pavements, defining requirements, criteria and indicators that are being treated in order to establish the value function by means of multi-criteria analysis.

  • Ensayo de doble punzamiento para caracterizar concreto reforzado con fibra. Nuevo método: ensayo Barcelona

     Aire, Carlos; Molins Borrell, Climent; Aguado De Cea, Antonio
    Congreso Nacional de Ingeniería Civil
    Presentation's date: 2013-11-27
    Presentation of work at congresses

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  • Experimental analysis of the flexural behavior of FRC+RC beams

     Pujadas Alvarez, Pablo; Blanco Álvarez, Ana; Pialarissi Cavalaro, Sergio Henrique; de la Fuente Antequera, Alberto; Aguado De Cea, Antonio; Soares Klein, Nayara
    Congresso Brasileiro do Concreto
    Presentation's date: 2013-10-29
    Presentation of work at congresses

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    La acción de las armaduras convencionales y de las fibras es complementaria a efectos de evitar la rotura frágil del hormigón. Las fibras, en tipo y cuantía adecuada, garantizan una clara responsabilidad estructural. Éstas, al añadirse al hormigón se dispersan en su volumen y confieren a dicha matriz un armado en tres dimensiones. Ello repercute en un incremento de la tenacidad y, por ende, un mejor control de la fisuración pues, contrariamente a lo que sucede con un armado convencional, las fibras trabajan en todo el bloque traccionado. En este sentido, la combinación de fibras y armadura convencional se presenta como una solución estructural y económicamente competitiva en el diseño de estructuras. En estas configuraciones mixtas (armado convencional y fibras), el armado convencional aporta en gran medida la capacidad resistente, sin embargo, gracias a la contribución estructural de las fibras, las cuantías de armado convencional necesarias pueden ser significativamente reducidas. Además, las fibras contribuyen, sin duda, a reducir los costes y problemas asociados de la manipulación de ferralla (traslado, doblado, soldaduras, colocación de separadores, entre otros), economizando tiempo y reduciendo los accidentes laborales derivados de este tipo de montajes. En los últimos años se han realizado numerosas investigaciones en la línea de sustituir total o parcialmente el armado tradicional del hormigón por fibras. Sin embargo, existe un gran desconocimiento e incertidumbre sobre el comportamiento a flexión de elementos tipo viga reforzados con armadura convencional y macro-fibras plásticas estructurales, de las que no existe actualmente investigación al respecto. En este trabajo se aborda el análisis de la solución anteriormente mencionada a través del estudio de los estados límite último y de servicio. Para ello, un total de 10 losas (3 x 1 x 0,2 m) de hormigón fueron producidos con diferentes configuraciones de refuerzo, tipos de fibras (acero y plásticas) y la dosificación de fibra utilizada (0.25% y 0,50%). Estas losas se ensayaron bajo la configuración de un ensayo a flexión de cuatro puntos.

    La acción de las armaduras convencionales y de las fibras es complementaria a efectos de evitar la rotura frágil del hormigón. Las fibras, en tipo y cuantía adecuada, garantizan una clara responsabilidad estructural. Éstas, al añadirse al hormigón se dispersan en su volumen y confieren a dicha matriz un armado en tres dimensiones. Ello repercute en un incremento de la tenacidad y, por ende, un mejor control de la fisuración pues, contrariamente a lo que sucede con un armado convencional, las fibras trabajan en todo el bloque traccionado. En este sentido, la combinación de fibras y armadura convencional se presenta como una solución estructural y económicamente competitiva en el diseño de estructuras. En estas configuraciones mixtas (armado convencional y fibras), el armado convencional aporta en gran medida la capacidad resistente, sin embargo, gracias a la contribución estructural de las fibras, las cuantías de armado convencional necesarias pueden ser significativamente reducidas. Además, las fibras contribuyen, sin duda, a reducir los costes y problemas asociados de la manipulación de ferralla (traslado, doblado, soldaduras, colocación de separadores, entre otros), economizando tiempo y reduciendo los accidentes laborales derivados de este tipo de montajes. En los últimos años se han realizado numerosas investigaciones en la línea de sustituir total o parcialmente el armado tradicional del hormigón por fibras. Sin embargo, existe un gran desconocimiento e incertidumbre sobre el comportamiento a flexión de elementos tipo viga reforzados con armadura convencional y macro-fibras plásticas estructurales, de las que no existe actualmente investigación al respecto. En este trabajo se aborda el análisis de la solución anteriormente mencionada a través del estudio de los estados límite último y de servicio. Para ello, un total de 10 losas (3 x 1 x 0,2 m) de hormigón fueron producidos con diferentes configuraciones de refuerzo, tipos de fibras (acero y plásticas) y la dosificación de fibra utilizada (0.25% y 0,50%). Estas losas se ensayaron bajo la configuración de un ensayo a flexión de cuatro puntos.

  • Mix-design and application of heavyweight concrete with density 4,000 and 4,500 kg/m3

     Soares Klein, Nayara; Aguado De Cea, Antonio; Pujadas Alvarez, Pablo; Soares, Talita C.
    Congresso Brasileiro do Concreto
    Presentation's date: 2013-10-29
    Presentation of work at congresses

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    Heavyweight concretes are an attractive alternative when heavyweight elements need to fill reduced spaces, because they present high densities and are able to take different forms according to the container where they are casted. The intended application for the heavyweight concrete referred to in this work is a power converter, which is a floating system that generates power through the waves of the sea. The design of this converter considers the use of elements of high mass at both ends of a metallic oval structure. Therefore, a heavyweight concrete with density of 4,000 and 4,500 kg/m3 was developed. For heavyweight concrete production with densities as high as the ones needed, it is necessary to use artificial aggregates of steel grit or corundum. Natural heavyweight aggregates such as hematite, magnetite or barite allow achieving maximum densities around 3,800 kg/m3, being unsuitable for the required application. For this reason, grit coarse aggregate 6-8 mm was used and a portion of the sand was replaced by a corundum fine aggregate 0.5-1.5 mm, being these materials out of the standard applications. In addition to the density requirements, consistency of the fresh concrete is also important as the use of heavyweight aggregates, whose density differs from the density of the mortar or paste, may lead to segregation of the mix. Due to the particularities of the concrete, the mix-design process was oriented to the specific application and quantitative and qualitative requirements were evaluated such as concepts related to the availability of the component materials, accessibility to the production area and casting. Therefore, the aim of this work is to present the considerations made during the mix-design process as well as the characterization of the heavyweight concretes produced, which showed results in agreement with the pre-established requirements.

    Heavyweight concretes are an attractive alternative when heavyweight elements need to fill reduced spaces, because they present high densities and are able to take different forms according to the container where they are casted. The intended application for the heavyweight concrete referred to in this work is a power converter, which is a floating system that generates power through the waves of the sea. The design of this converter considers the use of elements of high mass at both ends of a metallic oval structure. Therefore, a heavyweight concrete with density of 4,000 and 4,500 kg/m3 was developed. For heavyweight concrete production with densities as high as the ones needed, it is necessary to use artificial aggregates of steel grit or corundum. Natural heavyweight aggregates such as hematite, magnetite or barite allow achieving maximum densities around 3,800 kg/m3, being unsuitable for the required application. For this reason, grit coarse aggregate 6-8 mm was used and a portion of the sand was replaced by a corundum fine aggregate 0.5-1.5 mm, being these materials out of the standard applications. In addition to the density requirements, consistency of the fresh concrete is also important as the use of heavyweight aggregates, whose density differs from the density of the mortar or paste, may lead to segregation of the mix. Due to the particularities of the concrete, the mix-design process was oriented to the specific application and quantitative and qualitative requirements were evaluated such as concepts related to the availability of the component materials, accessibility to the production area and casting. Therefore, the aim of this work is to present the considerations made during the mix-design process as well as the characterization of the heavyweight concretes produced, which showed results in agreement with the pre-established requirements.

  • Influence of temperature on the assessment of fibre content and orientation with the inductive method

     Pialarissi Cavalaro, Sergio Henrique; López Carreño, Rubén - Daniel; Torrents Dolz, Josep Maria; Aguado De Cea, Antonio
    International Conference Fibre Concrete
    Presentation's date: 2013-09-12
    Presentation of work at congresses

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