The Experts below are selected from a list of 723 Experts worldwide ranked by ideXlab platform

Miguel Angel Climent - One of the best experts on this subject based on the ideXlab platform.

  • Short-Term Behavior of Slag Concretes Exposed to a Real In Situ Mediterranean Climate Environment
    Materials, 2017
    Co-Authors: José Marcos Ortega, Mar Cabeza, Isidro Sanchez, Miguel Angel Climent
    Abstract:

    At present, one of the most suitable ways to get a more sustainable cement industry is to reduce the CO2 emissions generated during cement production. In order to reach that goal, the use of ground granulated blast-furnace slag as clinker replacement is becoming increasingly popular. Although the effects of this addition in the properties of cementitious materials are influenced by their hardening conditions, there are not too many experimental studies in which slag concretes have been exposed to real in situ environments. Then, the main objective of this research is to study the short-term effects of exposure to real Mediterranean climate environment of an urban site, where the action of airborne chlorides from sea water and the presence of CO2 are combined, in the microstructure and service properties of a commercial slag cement concrete, compared to ordinary Portland cement (OPC). The microstructure was studied with mercury intrusion porosimetry. The effective porosity, capillary suction coefficient, chloride migration coefficient, Carbonation Front depth, and compressive strength were also analyzed. Considering the results obtained, slag concretes exposed to a real in situ Mediterranean climate environment show good service properties in the short-term (180 days), in comparison with OPC.

José Marcos Ortega - One of the best experts on this subject based on the ideXlab platform.

  • Short-Term Behavior of Slag Concretes Exposed to a Real In Situ Mediterranean Climate Environment
    Materials, 2017
    Co-Authors: José Marcos Ortega, Mar Cabeza, Isidro Sanchez, Miguel Angel Climent
    Abstract:

    At present, one of the most suitable ways to get a more sustainable cement industry is to reduce the CO2 emissions generated during cement production. In order to reach that goal, the use of ground granulated blast-furnace slag as clinker replacement is becoming increasingly popular. Although the effects of this addition in the properties of cementitious materials are influenced by their hardening conditions, there are not too many experimental studies in which slag concretes have been exposed to real in situ environments. Then, the main objective of this research is to study the short-term effects of exposure to real Mediterranean climate environment of an urban site, where the action of airborne chlorides from sea water and the presence of CO2 are combined, in the microstructure and service properties of a commercial slag cement concrete, compared to ordinary Portland cement (OPC). The microstructure was studied with mercury intrusion porosimetry. The effective porosity, capillary suction coefficient, chloride migration coefficient, Carbonation Front depth, and compressive strength were also analyzed. Considering the results obtained, slag concretes exposed to a real in situ Mediterranean climate environment show good service properties in the short-term (180 days), in comparison with OPC.

J H M Visser - One of the best experts on this subject based on the ideXlab platform.

  • influence of the carbon dioxide concentration on the resistance to Carbonation of concrete
    Construction and Building Materials, 2014
    Co-Authors: J H M Visser
    Abstract:

    Carbonation of concrete at ambient CO2 concentration is a slow process. This makes the testing of the resistance of concrete against Carbonation often too slow to be applicable for service life assessments of new structures. Raising the CO2-concentration will accelerate the test but the validity of an increase CO2-level is debated. If not valid, the service life can be seriously underestimated. In this paper, the effects of accelerating on the Carbonation process are discussed. It is shown that a change in CO2 concentration will not change the Carbonation process. Since Carbonation occurs instantly, a zero CO2 concentration at the Carbonation Front is maintained. Moreover, it has been concluded that all hydrated and unhydrated cement ultimately carbonates. This implies that the amount of material that can carbonate can be determined on the basis of the amount of calcium in the unreacted cement. © 2013 Elsevier Ltd. All rights reserved.

  • influence of the carbon dioxide concentration on the resistance to Carbonation of concrete
    SCMT3: International Conference of Sustainable Materials and Technologies Kyoto August 2013 1-10, 2013
    Co-Authors: J H M Visser
    Abstract:

    Carbonation of concrete at ambient CO2 concentration is a slow process. This makes the testing of the resistance of concrete against Carbonation often too slow to be applicable for service life assessments of new structures. Raising the CO2-concentration will accelerate the test but the validity of an increase CO2 -level is debated. If not valid, the service life can be seriously underestimated. In this paper, the effects of accelerating on the Carbonation process are discussed. It is shown that a change in CO2 concentration will not change the Carbonation process. Since Carbonation occurs instantly, a zero CO2 concentration at the Carbonation Front is maintained. Moreover, it has been concluded that all hydrated and unhydrated cement ultimately carbonate. This implies that the amount of carbonatable matter can be determined on the basis of the amount of calcium in the unreacted cement.

  • Accelerated Carbonation testing of mortar with supplementary cement materials. Limitation of the acceleration due to drying
    2012
    Co-Authors: J H M Visser
    Abstract:

    In the design stage of a concrete structure, decisions have to be made on how to fulfil the required service life and consequently, what concrete composition to use. Concrete compositions can be chosen on account of known performances but this will limit the choice of compositions and materials to those that have already been in use. Other methods may give a wider choice in concrete compositions, but mostly require proof which is generally obtained by means of testing. When limited time is available for testing, accelerated tests often are performed. If there is no good insight in the underlying principles of the effect of the acceleration, some serious mistakes in the service life designs will be made. In this paper, an example of accelerated testing is shown for Carbonation. Accelerated Carbonation tests at 2% CO2 and natural Carbonation tests at ambient CO2-level have been executed. Based on the results, the resistance against Carbonation has been calculated. Since this resistance is a material property, it should be similar in both tests. For two of the tested concrete compositions this proved to be the case, a third type of concrete made with fine cement it did, however, not. It was speculated that in the accelerated test, a different mechanism was becoming dominant for this concrete. Instead of the transport of CO2, now drying out was thought to be dominant. The drying out is a necessary step in the Carbonation process as during the Carbonation a relatively large amount of water is generated that, when saturating the pore space, prohibits CO2 to be transported to the Carbonation Front. A new simple model was derived for this case. The modelling gave a similar resistance against Carbonation for the fine OPC as determined in the natural Carbonation case where transport of CO2 was the dominant step in the Carbonation process. If this change in dominant step had not been made, a far too high resistance in Carbonation would have been calculated, seriously overestimating the service life of this fine OPC concrete in structural applications

Mar Cabeza - One of the best experts on this subject based on the ideXlab platform.

  • Short-Term Behavior of Slag Concretes Exposed to a Real In Situ Mediterranean Climate Environment
    Materials, 2017
    Co-Authors: José Marcos Ortega, Mar Cabeza, Isidro Sanchez, Miguel Angel Climent
    Abstract:

    At present, one of the most suitable ways to get a more sustainable cement industry is to reduce the CO2 emissions generated during cement production. In order to reach that goal, the use of ground granulated blast-furnace slag as clinker replacement is becoming increasingly popular. Although the effects of this addition in the properties of cementitious materials are influenced by their hardening conditions, there are not too many experimental studies in which slag concretes have been exposed to real in situ environments. Then, the main objective of this research is to study the short-term effects of exposure to real Mediterranean climate environment of an urban site, where the action of airborne chlorides from sea water and the presence of CO2 are combined, in the microstructure and service properties of a commercial slag cement concrete, compared to ordinary Portland cement (OPC). The microstructure was studied with mercury intrusion porosimetry. The effective porosity, capillary suction coefficient, chloride migration coefficient, Carbonation Front depth, and compressive strength were also analyzed. Considering the results obtained, slag concretes exposed to a real in situ Mediterranean climate environment show good service properties in the short-term (180 days), in comparison with OPC.

Isidro Sanchez - One of the best experts on this subject based on the ideXlab platform.

  • Short-Term Behavior of Slag Concretes Exposed to a Real In Situ Mediterranean Climate Environment
    Materials, 2017
    Co-Authors: José Marcos Ortega, Mar Cabeza, Isidro Sanchez, Miguel Angel Climent
    Abstract:

    At present, one of the most suitable ways to get a more sustainable cement industry is to reduce the CO2 emissions generated during cement production. In order to reach that goal, the use of ground granulated blast-furnace slag as clinker replacement is becoming increasingly popular. Although the effects of this addition in the properties of cementitious materials are influenced by their hardening conditions, there are not too many experimental studies in which slag concretes have been exposed to real in situ environments. Then, the main objective of this research is to study the short-term effects of exposure to real Mediterranean climate environment of an urban site, where the action of airborne chlorides from sea water and the presence of CO2 are combined, in the microstructure and service properties of a commercial slag cement concrete, compared to ordinary Portland cement (OPC). The microstructure was studied with mercury intrusion porosimetry. The effective porosity, capillary suction coefficient, chloride migration coefficient, Carbonation Front depth, and compressive strength were also analyzed. Considering the results obtained, slag concretes exposed to a real in situ Mediterranean climate environment show good service properties in the short-term (180 days), in comparison with OPC.