The Experts below are selected from a list of 1428 Experts worldwide ranked by ideXlab platform

Alexandros Sofianos - One of the best experts on this subject based on the ideXlab platform.

  • Comparison of Fire Resistant Geopolymers for Passive Fire Protection of Concrete Tunnel Linings
    Open Access Library Journal, 2017
    Co-Authors: Konstantinos Sakkas, P. P. Nomikos, Dimitris Panias, Alexandros Sofianos
    Abstract:

    Fire resistant geopolymers are developed and the performance under thermal loading is examined and compared in this paper. The geopolymers were prepared by mixing the solid phase, metallurgical slag and metakaolin with a highly alkaline potassium hydroxide aqueous phase in order to create a paste that was subsequently cured at 70℃ for a certain period of time. The developed materials were tested for the mechanical, physical and thermal properties. The behaviour of the geopolymers upon exposure on Fire was studied following the EFNARC guidelines for testing of Passive Fire Protection for concrete tunnels linings. The geopolymers were subjected to the most severe Fire scenario, the Rijks Water Staat (RWS) temperature-time curve. Both geopolymers appeared great behaviour after the test reaching temperature lower than the RWS test requirement, proving the ability of both materials to work successfully as an efficient thermal barrier. Thus, the concrete slab protected by the geopolymers did not appear any form of spalling or degradation of its compressive strength.

  • Behaviour of Passive Fire Protection K-Geopolymer under Successive Severe Fire Incidents
    Materials (Basel Switzerland), 2015
    Co-Authors: Konstantinos Sakkas, P. P. Nomikos, Alexandros Sofianos, Dimitrios Panias
    Abstract:

    The performance of a Fire resistant coating for tunnel Passive Fire Protection under successive severe thermal loading is presented. The material falls under the class of potassium based geopolymers (K-geopolymer) and was prepared by mixing ferronickel (FeNi) slag, doped with pure alumina, with a highly alkaline potassium hydroxide aqueous phase. Its performance was assessed by subjecting a concrete slab with a five cm thick K-geopolymer coating layer into successive RijksWaterStaat (RWS) Fire incidents. During the first test, the maximum measured temperature in the K-geopolymer/concrete interface was 250 °C, which is 130 °C lower than the RWS test requirement, while, during the second Fire test, the maximum temperature was almost 370 °C, which is still lower than the RWS requirement proving the effectiveness of the material as a thermal barrier. In addition, the material retained its structural integrity, during and after the two tests, without showing any mechanical or thermal damages.

  • potassium based geopolymer for Passive Fire Protection of concrete tunnels linings
    Tunnelling and Underground Space Technology, 2014
    Co-Authors: Konstantinos Sakkas, P. P. Nomikos, Dimitrios Panias, Alexandros Sofianos
    Abstract:

    Abstract The design of a Fire resistant coating for tunnel Passive Fire Protection and its performance under thermal loading are presented. The material falls under the class of potassium based geopolymers (K-geopolymer) and was prepared by mixing ferronickel (FeNi) slag, doped with pure alumina, with a highly alkaline potassium hydroxide aqueous phase. The physical, mechanical and thermal properties of the K-geopolymer were determined and compared to those of some commercially available Fire resistant materials. Its behavior upon exposure to Fire was assessed by subjecting a concrete slab, coated with a 5 cm thick K-geopolymer layer, to thermal loading under the RijksWaterStaat (RWS) temperature–time curve, which is considered as the most severe prescribed tunnel Fire scenario. During the test, the geopolymer/concrete interface temperature remained under 280 °C, which is 100 °C lower than the RWS test requirement, proving the effectiveness of the material as a thermal barrier. In addition, the K-geopolymer retained its structural integrity after the test, without any significant macroscopic damage.

  • Utilisation of FeNi-Slag for the Production of Inorganic Polymeric Materials for Construction or for Passive Fire Protection
    Waste and Biomass Valorization, 2014
    Co-Authors: Konstantinos Sakkas, Alexandros Sofianos, Pavlos Nomikos, Dimitrios Panias
    Abstract:

    This paper deals with the utilisation of ferronickel slag for the production of inorganic polymeric materials, with advanced mechanical or thermal properties, intended either for construction or for Passive Fire Protection respectively. Initially, the development of Fe–Ni slag-based geopolymers, achieving high compressive strength and low water absorption, is described, and the produced materials are compared with some common construction and building materials. Secondly, the development of two Fire resistant geopolymer materials is described. Their mechanical strength and thermal conductivity were measured, and the materials were tested for their resistance under high temperatures according to a standardized Fire resistance test, by employing two different thermal loading curves. The Fire resistant geopolymers were shown to comply with the test criteria concerning the temperature in the unexposed face of the specimen, the structural integrity and the concrete Protection from mechanical damages. They also achieved similar or even better mechanical strength and thermal conductivity compared with the commercially available Fire resistant materials.

  • Sodium-based Fire resistant geopolymer for Passive Fire Protection
    Fire and Materials, 2014
    Co-Authors: Konstantinos Sakkas, P. P. Nomikos, Alexandros Sofianos, Dimitrios Panias
    Abstract:

    Summary This paper primarily deals with the examination of the performance under thermal loading of a Fire resistant sodium-based geopolymer from Ferronickel slag. In addition, the mechanical, physical and thermal properties of material and their respective variation with time were measured. It is shown that the material presents good mechanical strength and excellent physical and thermal properties. The behaviour of the material on Fire was tested by subjecting it to thermal loading with the modification of a standardized Passive Fire Protection test. Two different Fire scenarios were investigated: (1) the least intensive standard ISO 834 Fire load curve and (2) the most severe Rijkswaterstaat Fire load curve. The material behaviour was excellent under its exposure at the ISO 834 Fire load curve, showing optimal thermal insulating function and very good structural integrity. Under the Rijkswaterstaat Fire load curve, the material showed again a very good thermal insulating function while at the same time suffered from creeping phenomena at the extremely high temperature of 1300°C that affected drastically its structural integrity. As a conclusion, the sodium-based geopolymer from FeNi slag may be an appropriate material for Passive Fire Protection systems under cellulosic Fires but inappropriate against more intense Fire incidents. Copyright © 2014 John Wiley & Sons, Ltd.

Joao R Correia - One of the best experts on this subject based on the ideXlab platform.

  • the effect of different Passive Fire Protection systems on the Fire reaction properties of gfrp pultruded profiles for civil construction
    Composites Part A-applied Science and Manufacturing, 2010
    Co-Authors: Joao R Correia, Fernando A Branco, J Ferreira
    Abstract:

    Abstract In order to study the viability of using GFRP pultruded profiles in floors of buildings, as structural elements, experimental investigations were carried out to analyse their behaviour when exposed to Fire. In particular, the feasibility and efficacy of using different protective coatings/layers (an intumescent coating, a vermiculite/perlite cement based mortar and a calcium silicate board) to provide Fire Protection to GFRP pultruded profiles was investigated. Previous experiments showed that the above mentioned Passive Fire Protection systems allow fulfilling Fire resistance requirements for the envisaged application. This paper presents the results of the investigations concerning the fulfilment of the Fire reaction requirements of those solutions. The experimental programme included dynamic mechanical analyses (DMA) and thermogravimetric and differential scanning calorimetry (TGA/DSC) experiments on both the GFRP and the Fire Protection materials. Subsequently, Fire reaction tests were carried out on GFRP pultruded laminates, both unprotected and protected with the different Fire Protection systems, using a cone calorimeter. Results of these experiments allowed defining the field of application of each investigated solution, according to building code requirements.

  • Fire Protection systems for building floors made of pultruded GFRP profiles – Part 2: Modeling of thermomechanical responses
    Composites Part B: Engineering, 2010
    Co-Authors: Yu Bai, Joao R Correia, Fernando A Branco, Thomas Keller, João Ferreira
    Abstract:

    A recently developed thermomechanical model to predict the time-dependent thermal and mechanical responses of pultruded glass fiber-reinforced polymer (GFRP) profiles subjected to Fire was extended to include the beneficial effects of Passive Fire Protection systems. The model extension was validated by comparing predicted and measured thermomechanical responses of pultruded GFRP tubes subjected to four-point bending and exposed to an ISO834 Fire from their underside. The profiles were protected using Passive and active methods, including a calcium silicate board, a vermiculite/perlite-based mortar, and a water-cooling system. Variations resulted mainly from the unavailability of accurate time-dependent thermophysical properties for the Protection materials. The benefits provided by the Fire Protection systems could be quantified and the model therefore can be used for the selection and design of Passive Fire Protection measures.

Konstantinos Sakkas - One of the best experts on this subject based on the ideXlab platform.

  • Comparison of Fire Resistant Geopolymers for Passive Fire Protection of Concrete Tunnel Linings
    Open Access Library Journal, 2017
    Co-Authors: Konstantinos Sakkas, P. P. Nomikos, Dimitris Panias, Alexandros Sofianos
    Abstract:

    Fire resistant geopolymers are developed and the performance under thermal loading is examined and compared in this paper. The geopolymers were prepared by mixing the solid phase, metallurgical slag and metakaolin with a highly alkaline potassium hydroxide aqueous phase in order to create a paste that was subsequently cured at 70℃ for a certain period of time. The developed materials were tested for the mechanical, physical and thermal properties. The behaviour of the geopolymers upon exposure on Fire was studied following the EFNARC guidelines for testing of Passive Fire Protection for concrete tunnels linings. The geopolymers were subjected to the most severe Fire scenario, the Rijks Water Staat (RWS) temperature-time curve. Both geopolymers appeared great behaviour after the test reaching temperature lower than the RWS test requirement, proving the ability of both materials to work successfully as an efficient thermal barrier. Thus, the concrete slab protected by the geopolymers did not appear any form of spalling or degradation of its compressive strength.

  • Behaviour of Passive Fire Protection K-Geopolymer under Successive Severe Fire Incidents
    Materials (Basel Switzerland), 2015
    Co-Authors: Konstantinos Sakkas, P. P. Nomikos, Alexandros Sofianos, Dimitrios Panias
    Abstract:

    The performance of a Fire resistant coating for tunnel Passive Fire Protection under successive severe thermal loading is presented. The material falls under the class of potassium based geopolymers (K-geopolymer) and was prepared by mixing ferronickel (FeNi) slag, doped with pure alumina, with a highly alkaline potassium hydroxide aqueous phase. Its performance was assessed by subjecting a concrete slab with a five cm thick K-geopolymer coating layer into successive RijksWaterStaat (RWS) Fire incidents. During the first test, the maximum measured temperature in the K-geopolymer/concrete interface was 250 °C, which is 130 °C lower than the RWS test requirement, while, during the second Fire test, the maximum temperature was almost 370 °C, which is still lower than the RWS requirement proving the effectiveness of the material as a thermal barrier. In addition, the material retained its structural integrity, during and after the two tests, without showing any mechanical or thermal damages.

  • potassium based geopolymer for Passive Fire Protection of concrete tunnels linings
    Tunnelling and Underground Space Technology, 2014
    Co-Authors: Konstantinos Sakkas, P. P. Nomikos, Dimitrios Panias, Alexandros Sofianos
    Abstract:

    Abstract The design of a Fire resistant coating for tunnel Passive Fire Protection and its performance under thermal loading are presented. The material falls under the class of potassium based geopolymers (K-geopolymer) and was prepared by mixing ferronickel (FeNi) slag, doped with pure alumina, with a highly alkaline potassium hydroxide aqueous phase. The physical, mechanical and thermal properties of the K-geopolymer were determined and compared to those of some commercially available Fire resistant materials. Its behavior upon exposure to Fire was assessed by subjecting a concrete slab, coated with a 5 cm thick K-geopolymer layer, to thermal loading under the RijksWaterStaat (RWS) temperature–time curve, which is considered as the most severe prescribed tunnel Fire scenario. During the test, the geopolymer/concrete interface temperature remained under 280 °C, which is 100 °C lower than the RWS test requirement, proving the effectiveness of the material as a thermal barrier. In addition, the K-geopolymer retained its structural integrity after the test, without any significant macroscopic damage.

  • Utilisation of FeNi-Slag for the Production of Inorganic Polymeric Materials for Construction or for Passive Fire Protection
    Waste and Biomass Valorization, 2014
    Co-Authors: Konstantinos Sakkas, Alexandros Sofianos, Pavlos Nomikos, Dimitrios Panias
    Abstract:

    This paper deals with the utilisation of ferronickel slag for the production of inorganic polymeric materials, with advanced mechanical or thermal properties, intended either for construction or for Passive Fire Protection respectively. Initially, the development of Fe–Ni slag-based geopolymers, achieving high compressive strength and low water absorption, is described, and the produced materials are compared with some common construction and building materials. Secondly, the development of two Fire resistant geopolymer materials is described. Their mechanical strength and thermal conductivity were measured, and the materials were tested for their resistance under high temperatures according to a standardized Fire resistance test, by employing two different thermal loading curves. The Fire resistant geopolymers were shown to comply with the test criteria concerning the temperature in the unexposed face of the specimen, the structural integrity and the concrete Protection from mechanical damages. They also achieved similar or even better mechanical strength and thermal conductivity compared with the commercially available Fire resistant materials.

  • Sodium-based Fire resistant geopolymer for Passive Fire Protection
    Fire and Materials, 2014
    Co-Authors: Konstantinos Sakkas, P. P. Nomikos, Alexandros Sofianos, Dimitrios Panias
    Abstract:

    Summary This paper primarily deals with the examination of the performance under thermal loading of a Fire resistant sodium-based geopolymer from Ferronickel slag. In addition, the mechanical, physical and thermal properties of material and their respective variation with time were measured. It is shown that the material presents good mechanical strength and excellent physical and thermal properties. The behaviour of the material on Fire was tested by subjecting it to thermal loading with the modification of a standardized Passive Fire Protection test. Two different Fire scenarios were investigated: (1) the least intensive standard ISO 834 Fire load curve and (2) the most severe Rijkswaterstaat Fire load curve. The material behaviour was excellent under its exposure at the ISO 834 Fire load curve, showing optimal thermal insulating function and very good structural integrity. Under the Rijkswaterstaat Fire load curve, the material showed again a very good thermal insulating function while at the same time suffered from creeping phenomena at the extremely high temperature of 1300°C that affected drastically its structural integrity. As a conclusion, the sodium-based geopolymer from FeNi slag may be an appropriate material for Passive Fire Protection systems under cellulosic Fires but inappropriate against more intense Fire incidents. Copyright © 2014 John Wiley & Sons, Ltd.

João Ferreira - One of the best experts on this subject based on the ideXlab platform.

  • Fire Protection systems for building floors made of pultruded GFRP profiles – Part 2: Modeling of thermomechanical responses
    Composites Part B: Engineering, 2010
    Co-Authors: Yu Bai, Joao R Correia, Fernando A Branco, Thomas Keller, João Ferreira
    Abstract:

    A recently developed thermomechanical model to predict the time-dependent thermal and mechanical responses of pultruded glass fiber-reinforced polymer (GFRP) profiles subjected to Fire was extended to include the beneficial effects of Passive Fire Protection systems. The model extension was validated by comparing predicted and measured thermomechanical responses of pultruded GFRP tubes subjected to four-point bending and exposed to an ISO834 Fire from their underside. The profiles were protected using Passive and active methods, including a calcium silicate board, a vermiculite/perlite-based mortar, and a water-cooling system. Variations resulted mainly from the unavailability of accurate time-dependent thermophysical properties for the Protection materials. The benefits provided by the Fire Protection systems could be quantified and the model therefore can be used for the selection and design of Passive Fire Protection measures.

Fernando A Branco - One of the best experts on this subject based on the ideXlab platform.

  • the effect of different Passive Fire Protection systems on the Fire reaction properties of gfrp pultruded profiles for civil construction
    Composites Part A-applied Science and Manufacturing, 2010
    Co-Authors: Joao R Correia, Fernando A Branco, J Ferreira
    Abstract:

    Abstract In order to study the viability of using GFRP pultruded profiles in floors of buildings, as structural elements, experimental investigations were carried out to analyse their behaviour when exposed to Fire. In particular, the feasibility and efficacy of using different protective coatings/layers (an intumescent coating, a vermiculite/perlite cement based mortar and a calcium silicate board) to provide Fire Protection to GFRP pultruded profiles was investigated. Previous experiments showed that the above mentioned Passive Fire Protection systems allow fulfilling Fire resistance requirements for the envisaged application. This paper presents the results of the investigations concerning the fulfilment of the Fire reaction requirements of those solutions. The experimental programme included dynamic mechanical analyses (DMA) and thermogravimetric and differential scanning calorimetry (TGA/DSC) experiments on both the GFRP and the Fire Protection materials. Subsequently, Fire reaction tests were carried out on GFRP pultruded laminates, both unprotected and protected with the different Fire Protection systems, using a cone calorimeter. Results of these experiments allowed defining the field of application of each investigated solution, according to building code requirements.

  • Fire Protection systems for building floors made of pultruded GFRP profiles – Part 2: Modeling of thermomechanical responses
    Composites Part B: Engineering, 2010
    Co-Authors: Yu Bai, Joao R Correia, Fernando A Branco, Thomas Keller, João Ferreira
    Abstract:

    A recently developed thermomechanical model to predict the time-dependent thermal and mechanical responses of pultruded glass fiber-reinforced polymer (GFRP) profiles subjected to Fire was extended to include the beneficial effects of Passive Fire Protection systems. The model extension was validated by comparing predicted and measured thermomechanical responses of pultruded GFRP tubes subjected to four-point bending and exposed to an ISO834 Fire from their underside. The profiles were protected using Passive and active methods, including a calcium silicate board, a vermiculite/perlite-based mortar, and a water-cooling system. Variations resulted mainly from the unavailability of accurate time-dependent thermophysical properties for the Protection materials. The benefits provided by the Fire Protection systems could be quantified and the model therefore can be used for the selection and design of Passive Fire Protection measures.