Concrete Journal
Online ISSN : 2186-2753
Print ISSN : 0387-1061
ISSN-L : 0387-1061
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Volume 47, Issue 2
Displaying 1-17 of 17 articles from this issue
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  • Traceability Systems for Concrete
    K. Sakamura, T. Kimijima
    2009 Volume 47 Issue 2 Pages 2_3-2_6
    Published: 2009
    Released on J-STAGE: March 27, 2012
    DOIhttps://doi.org/10.3151/coj.47.2_3
    JOURNAL FREE ACCESS
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    This paper reviews the effectiveness of usage of RFID tags, ucode, a universal unique identification number, and ucode resolution mechanism for the purpose of realizing the traceability systems for concrete.
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  • Outline of : “Guidelines for Design and Construction of High-strength Concrete for Prestressed Concrete Structures”
    H. Mutsuyoshi, K. Ohtsuka, T. Ichinomiya, M. Sakurada
    2009 Volume 47 Issue 2 Pages 2_7-2_13
    Published: 2009
    Released on J-STAGE: March 27, 2012
    DOIhttps://doi.org/10.3151/coj.47.2_7
    JOURNAL FREE ACCESS
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    High-strength concrete with a design strength of more than 100N/mm2 has recently been applied practically to prestressed concrete bridges. Adopting high-strength concrete for prestressed concrete bridges enables lighter members, reduction in seismic force, use of longer spans, reduction in girder height and improved durability. Therefore, high value-added or high performance structures that cannot be realized with ordinary concrete can be constructed. However, no adequate design and construction guidelines for high-strength concrete have been established in Japan for prestressed concrete structures. Developing design and construction guidelines promptly is therefore required for the effective design and construction of prestressed concrete structures with high-strength concrete. Based on this background, the Japan Prestressed Concrete Engineering Association set up a committee on “Design and Construction for Prestressed Concrete Structures Using High-strength Concrete” in 2006 and the "Guidelines for Design and Construction of High-strength Concrete for Prestressed Concrete Structures" has just been published in October 2008. This paper presents an outline of the above-mentioned guidelines.
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  • Mechanical Properties and Color Evaluation of Concrete Colored by Using Waste Earthenware
    M. Inoue, T. Okamoto, K. Hirao, T. Kojima
    2009 Volume 47 Issue 2 Pages 2_14-2_20
    Published: 2009
    Released on J-STAGE: March 27, 2012
    DOIhttps://doi.org/10.3151/coj.47.2_14
    JOURNAL FREE ACCESS
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    The purpose of this study is the development of design structural material which has strength and durability in traditional landscape. In this study, the mechanical properties and the color evaluation of concrete colored by using the waste earthenware were examined. As a result, it was verified that the strength and durability of the colored concrete were equivalent to those of normal concrete. Furthermore, the color of the colored concrete was generally in agreement with that of wall materials in the traditional area.
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  • Estimation of Carbonation and Chloride Penetration of Recycled Aggregate Concrete Focused on Pore Volume
    Y. Sagawa, H. Matsushita, Y. Kawabata
    2009 Volume 47 Issue 2 Pages 2_21-2_29
    Published: 2009
    Released on J-STAGE: March 27, 2012
    DOIhttps://doi.org/10.3151/coj.47.2_21
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    In this study, several accelerated durability tests were performed to clarify the speed of carbonation and chloride ion penetration of recycled aggregate concrete. When the recycled aggregate with high absorption and low density was used, durability of concrete was lowered. This trend was remarkable when recycled fine aggregate was used. As the results of experiments on mortar, the increase of pore volume in new cement paste matrix lowered durability, and mineral admixtures, such as fly ash and ground granulated blast-furnace slag, improved resistance to chloride penetration. Moreover, it was confirmed that durability of pretensioned spunconcrete poles made by centrifugal compaction didn't fall remarkably if strength of recycled concrete was at the same level as that of normal aggregate concrete.
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  • Study on the Durability Improvement of Concrete Surface Covering Materials
    T. Kamamoto, S. Nojima, K. Fujita
    2009 Volume 47 Issue 2 Pages 2_30-2_36
    Published: 2009
    Released on J-STAGE: March 27, 2012
    DOIhttps://doi.org/10.3151/coj.47.2_30
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    East, Central, West Nippon Expressway Co. Ltd. established their own standards for concrete surface covering materials in 1988, and concrete surface covering material products which met the standards have been applied to their concrete bridge piers, etc. But recently it was found that even the approved products sometimes showed insufficient performance or effect at early stage. In order to investigate the durability of concrete surface covering material products, Nippon Expressway Research Institute Co. Ltd started a series of weathering tests of concrete surface covering material products in the market in 1997 and checked the condition after 10 years exposure in 2007. Based on the result of this weathering tests and the observation of the condition of concrete surface covering material products applied on the actual bridges about 10 years ago, we studied about the new test method to evaluate the durability of concrete surface covering material products.
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  • Study on Quick and Simple Method of Assessing Crack Index for Wall Type Massive Concrete Structures
    T. Ishida, Y. Tsuji
    2009 Volume 47 Issue 2 Pages 2_37-2_45
    Published: 2009
    Released on J-STAGE: March 27, 2012
    DOIhttps://doi.org/10.3151/coj.47.2_37
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    The possibility of a massive cracking caused by hydration heat of cement is generally checked on basis of thermal stress analysis. However, thermal stress analysis needs a great deal of time and effort, so a quicker assessment method is expected. In this paper, a quick method of assessing minimum crack index is proposed from analytical results for wall type structures. It was clarified that the temperature drop could be assumed by using the relation between wall thickness, curing condition and adiabatic temperature rise of concrete. The results indicated that a minimum crack index can be estimated from wall thickness, temperature drop strain, autogenous shrinkage and a restraint coefficient.
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  • Concept of Single Duct Structure in Saddle System
    S. Tamai, Y. Yamahana, M. Kato, M. Nishino
    2009 Volume 47 Issue 2 Pages 2_46-2_51
    Published: 2009
    Released on J-STAGE: March 27, 2012
    DOIhttps://doi.org/10.3151/coj.47.2_46
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    Tohoku-Shinkansen Sannaimaruyama Bridge is longest span Shinkansen Bridge. In this paper, new method of stay-cable fixed system that is Single duct structure in saddle system to main-tower are proposed. Stay cable is fixed by adhesion resistance of steel-pipe and Pull-out resistance of anchor-flange. Loading tests of members, which assumed large-scale earthquake, were conducted to verify the method. As the results, it was verified that Single duct structure in saddle system function sufficiently as stay-cable fixed system.
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