Concrete Journal
Online ISSN : 2186-2753
Print ISSN : 0387-1061
ISSN-L : 0387-1061
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Volume 49, Issue 8
Displaying 1-16 of 16 articles from this issue
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  • Method of Rapid Test for Identification of Alkali-silica Reactivity of Recycled Aggregate Class H
    Y. Kuroda, T. Mano, Y. Suzuki, T. Noguchi
    2011 Volume 49 Issue 8 Pages 8_3-8_8
    Published: 2011
    Released on J-STAGE: August 01, 2012
    DOIhttps://doi.org/10.3151/coj.49.8_3
    JOURNAL FREE ACCESS
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    Creating the proper method of an evaluation test of alkali-silica reactivity is required to promote the usage of recycle aggregate. Therefore, the JIS (Japanese Industrial Standards) draft revision committee of recycled aggregate conducted experiments on the effect of pessimum content which was based on “JIS A 1804 Method of test for production control of concrete—Method of rapid test for identification of alkali-silica reactivity of aggregate”. Also we proposed “the method of rapid test for identification of alkali-silica reactivity of recycled aggregate H” to become a part of “JIS A 5021 Recycled aggregate for concrete—class H” as one of the JIS draft revision plans of 2011.
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  • CO2 Uptake over Service Period of Concrete Structures and Recycling Process of Concrete Rubbles
    T. Kanda, S. Sone, H. Kishida
    2011 Volume 49 Issue 8 Pages 8_9-8_16
    Published: 2011
    Released on J-STAGE: August 01, 2012
    DOIhttps://doi.org/10.3151/coj.49.8_9
    JOURNAL FREE ACCESS
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    Although carbonation is a fundamental phenomenon for concrete structures, the amount of CO2 has not been quantified, which is absorbed in concrete structures and recycling concrete aggregates due to the phenomenon. In the present paper, we quantify uptake of CO2 over using phase and recycling process of concrete. We conduct TG-DTA analysis for on-site specimens widely collected around the nation. The following results are obtained. 1) Concrete structure absorbs 15kg-CO2/t through its using phase. On exposed concrete structures, CO2 uptake rate is twice as fast as that on buried ones. 2) Recycling concrete aggregate absorbs 9kg-CO2/t through recycling process consisting of demolition, crushing and temporary storage. The increment degree is primary governed by particle size of the recycling concrete aggregate.
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  • A Survey of Performance for Systems of Cathodic Protection on the Concrete Railway Bridge
    H. Fuda, Y. Shinoda, Y. Matsuda
    2011 Volume 49 Issue 8 Pages 8_17-8_22
    Published: 2011
    Released on J-STAGE: August 01, 2012
    DOIhttps://doi.org/10.3151/coj.49.8_17
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    Recently, cathodic protection method is attracting higher attention as a countermeasure to the drastic salt damage of a concrete structure. Limited number of literature is available on the long-term performance and analysis of the protection, despite the variety of CP methods. The present paper describes a long term test and analysis of CP applied to a railway bridge of prestressed concrete located on the coast of Sea of Japan where the most severe salt damage is reported. Analysis and discussion are given to the electrochemical data collected on site regularly for ten years of the test.
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  • Research on Stress State Evaluation for Highway PC Bridge
    T. Fujita, T. Tamakoshi, T. Tsutsumi
    2011 Volume 49 Issue 8 Pages 8_23-8_29
    Published: 2011
    Released on J-STAGE: August 01, 2012
    DOIhttps://doi.org/10.3151/coj.49.8_23
    JOURNAL FREE ACCESS
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    When it was predicted that structure performance deteriorated with the damage and transformation by the check of the highway PC bridge, sound evaluation for the bridge and to take repair/reinforcement measures are necessary. It is important to grasp the prestress state at the time of the investigation, and establishment to the estimate technique of the prestress state is necessary. This study inspected the possibility of the estimate of the prestress state from crack property by visual investigation, and strain behavior by the real bridge loading test. As a result, the possibility to become effective means to evaluate the structure performance of highway PC bridge and judge the presence of the decrease prestress were shown by the technique shown in this study.
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