Concrete Journal
Online ISSN : 2186-2753
Print ISSN : 0387-1061
ISSN-L : 0387-1061
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Volume 49, Issue 3
Displaying 1-15 of 15 articles from this issue
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  • Completion Inspection Method to Check Impermeability of Cover Concrete—Recommendations in Switzerland—
    K. Nakarai, I. Kurashige, T. Kishi
    2011 Volume 49 Issue 3 Pages 3_3-3_6
    Published: 2011
    Released on J-STAGE: March 01, 2012
    DOIhttps://doi.org/10.3151/coj.49.3_3
    JOURNAL FREE ACCESS
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    In Switzerland, the recommendations were published in order to check the impermeability of the cover concrete on the structure by means of permeability tests (e.g. air permeability measurements). Since this completion inspection can directly check the actual quality of the cover concrete, it is expected to contribute the certification and improvement of the durability of concrete structures and innovation in the concrete engineering. Here, the outline of the draft of guideline will be introduced.
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  • Revision of the Standard Specification for Reinforcing Bar Joint Work
    Y. Masuda, H. Narihara, J. Kadoriku, T. Sasaya
    2011 Volume 49 Issue 3 Pages 3_7-3_12
    Published: 2011
    Released on J-STAGE: March 01, 2012
    DOIhttps://doi.org/10.3151/coj.49.3_7
    JOURNAL FREE ACCESS
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    Japan Reinforcing Bar Joints Institute revised the standard specification for reinforcing bar joint work, i.e. gas pressure welded joint work, welded joint work and mechanical joint work in last year. Reinforcing bar joint work is important to secure safety of reinforced concrete structure. The main points of the revision are as follows. (1)Required performances of reinforcing bar joint are prescribed distinctly in the standard specification. (2)The quality control of reinforcing bar joint work is executed with unified system in three kinds of joint work. (3)Grade-A joint work companies are certified by Japan Reinforcing Bar Joints Institute and allowed to perform grade-A joint work. (4)Inspection is conducted under the witness of employer or the architect/engineer.
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  • Development of Large-scale Precast Concrete Skew Box Culvert with Looped Joint Connection
    Y. Sagawa, T. Katayama, T. Tsutsumi, H. Matsushita
    2011 Volume 49 Issue 3 Pages 3_13-3_20
    Published: 2011
    Released on J-STAGE: March 01, 2012
    DOIhttps://doi.org/10.3151/coj.49.3_13
    JOURNAL FREE ACCESS
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    Usually, many of the large box culverts with over 5m width are skewed, and in-situ concrete is used from the viewpoint of economic efficiency. However, precast concrete products can shorten a period of construction work and keep uniform quality. In this study, an economical precast concrete box culvert which could be applied for skew structures was developed. Top plate and side wall were segmented and both were connected by looped joint connection on the corner. First of all, the element experiment on looped joint connection system was conducted. After that, the full-scale specimen was assembled, and then construction performance and structural performance were investigated. As the results, the box culvert could be assembled as it was expected, and it had equivalent structural performance to the ordinary box culvert using in-situ concrete. Also, in order to the calculate stress resultant of large-scale box culvert, the method considering the rigid frame on elastic foundation was preferable.
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  • Water Supplying Concrete Curing System—Practical Use and Effects of Water Supplying Concrete Curing System after Removal of Form—
    Y. Furukawa, K. Fukudome, A. Shono
    2011 Volume 49 Issue 3 Pages 3_21-3_28
    Published: 2011
    Released on J-STAGE: March 01, 2012
    DOIhttps://doi.org/10.3151/coj.49.3_21
    JOURNAL FREE ACCESS
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    Concrete Curing System with supplying water to the surface of concrete, which stands vertically and/or slantingly immediately after removal of form, in order to maintain the surface wet was developed. This system will be functioned with forming water-membrane on the concrete surface as follows. The curing sheet inundated with water will adhere firmly to the concrete surface by absorbing the air remains between the concrete surface and the curing sheet. And the water-membrane will be formed on the concrete surface with supplying the water to the closed space under the curring sheet. This concrete curing system enables the supplying water to be distributed concrete surface, which stands vertically or slantingly with providing the full sized curing system. As a result, it is confirmed that the concrete employed this curing system was enhanced of concrete strength and durability. In addition, it was confirmed to be excellent in the practicality by the trial tests in a real structure.
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