Concrete Journal
Online ISSN : 2186-2753
Print ISSN : 0387-1061
ISSN-L : 0387-1061
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Volume 52, Issue 4
Displaying 1-13 of 13 articles from this issue
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  • JIS A 1158 (Method for reducing samples of aggregate to testing size)
    H. Kawano, M. Hayakawa, T. Mano, T. Kage
    2014 Volume 52 Issue 4 Pages 297-302
    Published: 2014
    Released on J-STAGE: April 01, 2015
    DOIhttps://doi.org/10.3151/coj.52.297
    JOURNAL FREE ACCESS
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    Aggregate to be subjected to testing must be representative of the lot to be tested, and if the reduction of the sample of aggregate is done improperly, accurate assessment of the quality of that lot of aggregate is not possible. In other words, the obtainment of accurate test results requires the standardization of not only the test conditions, but also the aggregate sample reduction method. This paper outlines the contents of the JIS A 1158 (Method for reducing samples of aggregate to testing size) standard, which covers the aggregate sample reduction method.
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  • Cracking Control Technology for Concrete Using Urea
    H. Tanaka, T. Ayano
    2014 Volume 52 Issue 4 Pages 303-308
    Published: 2014
    Released on J-STAGE: April 01, 2015
    DOIhttps://doi.org/10.3151/coj.52.303
    JOURNAL FREE ACCESS
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    Cracking of concrete structures not only affects the appearance of such structures but also lowers their performance, such as long-term durability and water tightness. To achieve durable concrete structures that are both strong and of good appearance, it is important to minimize the occurrence of cracks. Focusing on the high water solubility, non-volatility, and endothermic reaction of urea, the authors have developed technology that can reduce drying shrinkage-induced cracking through the inhibitory effect of the non-volatility of urea on moisture dissipation inside concrete, and also reduce thermal cracking through the endothermic reaction of urea, which reduces concrete temperature, as well as urea's hydration delaying effect, which reduces hydration heat during concrete production.
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  • Practical Use of Databases to Ensure the Quality of Concrete Structures
    T. Tamura, A. Hosoda, M. Ninomiya, H. Nakamura
    2014 Volume 52 Issue 4 Pages 309-315
    Published: 2014
    Released on J-STAGE: April 01, 2015
    DOIhttps://doi.org/10.3151/coj.52.309
    JOURNAL FREE ACCESS
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    The issues to be solved in the field of concrete engineering are extremely diverse, ranging from issues related to the safety of structural members to durability related issues, and many of these issues are solved through experimental observation and data analysis. Further, the elucidation of issues requires the determination of appropriate analysis methods to determine causal relationships according to the theme at hand. In recent years, advances in information technology have made it possible to handle huge amounts of data. Moreover, research on technologies to monitor existing structures is also making progress. However, an important point is how these various advances are utilized. This paper introduces cases of existing research on the use of databases in the field of concrete engineering, with a particular focus on statistical techniques for ensuring the quality of structures.
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