The Experts below are selected from a list of 6366 Experts worldwide ranked by ideXlab platform

Surendra P Shah - One of the best experts on this subject based on the ideXlab platform.

  • prediction of early age Cracking of fiber reinforced concrete due to restrained shrinkage
    Aci Materials Journal, 2008
    Co-Authors: Seung Hee Kwon, Surendra P Shah
    Abstract:

    Fibers are increasingly being added to concrete mixtures enhance the Cracking resistance of concrete. In this study, a method to predict Cracking of fiber-reinforced concrete due to restrained drying shrinkage is proposed, and a comparison between test data and analysis results is made. In the prediction, major influencing factors on Cracking, drying shrinkage based on moisture diffusion, Creep, Cracking resistance of concrete, and the effect of added fiber were incorporated. It is shown that the results obtained from the incorporated models can predict the Cracking time and crack width varying over time of plain and fiber-reinforced concrete in a satisfactory manner.

  • Cracking of fiber reinforced self compacting concrete due to restrained shrinkage
    International Journal of Concrete Structures and Materials, 2007
    Co-Authors: Seung Hee Kwon, Raissa Ferron, Yilmaz Akkaya, Surendra P Shah
    Abstract:

    Fiber-reinforced self-compacting concrete (FRSCC) is a new type of concrete mix that can mitigate two opposing weaknesses: poor workability in fiber-reinforced concrete and Cracking resistance in plain SCC concrete. This study focused on early-age Cracking of FRSCC due to restrained drying shrinkage, one of the most common causes of Cracking. In order to investigate the effect of fiber on shrinkage Cracking of FRSCC, ring shrinkage tests were performed for polypropylene and steel fiber-reinforced SCC. In addition, finite element analyses for those specimens were carried out considering drying shrinkage based on moisture diffusion, Creep, Cracking resistance of concrete, and the effect of fiber. The analysis results were verified via a comparison between the measured and calculated crack width. From the test and analysis results, the effectiveness of fiber with respect to reducing Cracking was confirmed and some salient features on the shrinkage Cracking of FRSCC were obtained.

Seung Hee Kwon - One of the best experts on this subject based on the ideXlab platform.

  • prediction of early age Cracking of fiber reinforced concrete due to restrained shrinkage
    Aci Materials Journal, 2008
    Co-Authors: Seung Hee Kwon, Surendra P Shah
    Abstract:

    Fibers are increasingly being added to concrete mixtures enhance the Cracking resistance of concrete. In this study, a method to predict Cracking of fiber-reinforced concrete due to restrained drying shrinkage is proposed, and a comparison between test data and analysis results is made. In the prediction, major influencing factors on Cracking, drying shrinkage based on moisture diffusion, Creep, Cracking resistance of concrete, and the effect of added fiber were incorporated. It is shown that the results obtained from the incorporated models can predict the Cracking time and crack width varying over time of plain and fiber-reinforced concrete in a satisfactory manner.

  • Cracking of fiber reinforced self compacting concrete due to restrained shrinkage
    International Journal of Concrete Structures and Materials, 2007
    Co-Authors: Seung Hee Kwon, Raissa Ferron, Yilmaz Akkaya, Surendra P Shah
    Abstract:

    Fiber-reinforced self-compacting concrete (FRSCC) is a new type of concrete mix that can mitigate two opposing weaknesses: poor workability in fiber-reinforced concrete and Cracking resistance in plain SCC concrete. This study focused on early-age Cracking of FRSCC due to restrained drying shrinkage, one of the most common causes of Cracking. In order to investigate the effect of fiber on shrinkage Cracking of FRSCC, ring shrinkage tests were performed for polypropylene and steel fiber-reinforced SCC. In addition, finite element analyses for those specimens were carried out considering drying shrinkage based on moisture diffusion, Creep, Cracking resistance of concrete, and the effect of fiber. The analysis results were verified via a comparison between the measured and calculated crack width. From the test and analysis results, the effectiveness of fiber with respect to reducing Cracking was confirmed and some salient features on the shrinkage Cracking of FRSCC were obtained.

Nicolas Roussel - One of the best experts on this subject based on the ideXlab platform.

  • properties of fresh and hardened concrete
    Cement and Concrete Research, 2011
    Co-Authors: Konstantin Kovler, Nicolas Roussel
    Abstract:

    Abstract The present paper reviews the literature related to the properties of fresh and hardened concrete published after the previous (12th) International Congress on the Chemistry of Cement held in Montreal in 2007. Workability and fundamental rheological properties, reversible and non-reversible evolution, thixotropy, slump loss, setting time, bleeding, segregation and practical issues related to formwork filling and pressure, are addressed among the properties of fresh concrete. Among hardened concrete properties compressive strength and other mechanical and physical properties of hardened concrete, such as tensile strength, elastic properties, shrinkage, Creep, Cracking resistance, electrical, thermal, transport and other properties are covered. Testing, interpretation, modeling and prediction of properties are addressed, as well as correlation with properties of fresh concrete and durability, effects of special binders, recycled and natural aggregates, fiber reinforcement, mineral and chemical admixtures. Special attention is given to the properties of hardened lightweight and self-compacting concrete.

E A Grin - One of the best experts on this subject based on the ideXlab platform.

  • an approach to assessment of the lifetime characteristics of steels under Creep conditions using fracture mechanics criteria
    Thermal Engineering, 2018
    Co-Authors: A A Lanin, E A Grin
    Abstract:

    The current status of activities associated with the assessment of conditions and prospects for prolonging the service life of equipment operating for a long time at thermal power stations (TPS) is described. The history of the creation and development of an industry system for diagnosing and prolonging the lifetime of heat-generating and mechanical equipment is briefly outlined. The core of the system was the results of investigations into long-term strength and Creep of heat-resistant steels, and a regulatory base governing effective application of the system was formed and continuously improved within the system framework. It is noted that more and more extensive investigations resulted in the attempts to extend the criterial strength base using the Cracking resistance criteria, including local Creep fracture criteria. The advantages and disadvantages of the most-used local control method, i.e., the replica method, are analyzed. It is proposed to use the fracture mechanics criteria and, in particular, the threshold stress intensity factor (SIF) below which Creep Cracking does not occur in analyzing the process of steel Creep fracture. It is demonstrated that the threshold SIF for a specific material depends functionally not only on the temperature but also on the loading time. Considering this fact, it is proposed to account for the accumulation of local (at the crack tip) and total damageability of the metal in the concept of threshold SIF. A similar approach can also be used for describing the subcritical crack growth. Therefore, it is proposed to construct crack growth diagrams using isochronous curves for the specified test times. It is demonstrated that dimensions of allowable flaws that do not lead to crack propagation can be predicted for given operating conditions. The cases were analyzed that occurred while obtaining results of examination of a structural member operating under Creep conditions for prediction of the size of allowable (nonpropagating) crack-like flaws. This analysis has revealed that the application of the threshold SIF criterion and isochronous Creep crack growth rate diagrams can be useful for setting forth the substantiated frequency of examinations for high-temperature equipment and establishing the time by which the equipment service life can be prolonged.

Konstantin Kovler - One of the best experts on this subject based on the ideXlab platform.

  • properties of fresh and hardened concrete
    Cement and Concrete Research, 2011
    Co-Authors: Konstantin Kovler, Nicolas Roussel
    Abstract:

    Abstract The present paper reviews the literature related to the properties of fresh and hardened concrete published after the previous (12th) International Congress on the Chemistry of Cement held in Montreal in 2007. Workability and fundamental rheological properties, reversible and non-reversible evolution, thixotropy, slump loss, setting time, bleeding, segregation and practical issues related to formwork filling and pressure, are addressed among the properties of fresh concrete. Among hardened concrete properties compressive strength and other mechanical and physical properties of hardened concrete, such as tensile strength, elastic properties, shrinkage, Creep, Cracking resistance, electrical, thermal, transport and other properties are covered. Testing, interpretation, modeling and prediction of properties are addressed, as well as correlation with properties of fresh concrete and durability, effects of special binders, recycled and natural aggregates, fiber reinforcement, mineral and chemical admixtures. Special attention is given to the properties of hardened lightweight and self-compacting concrete.