Concrete Journal
Online ISSN : 2186-2753
Print ISSN : 0387-1061
ISSN-L : 0387-1061
Volume 59, Issue 12
Displaying 1-11 of 11 articles from this issue
Preface
TOPICS
  • T. Ogata, K. Kubo, R. Shionaga, H. Higashiyama
    2021 Volume 59 Issue 12 Pages 985-990
    Published: 2021
    Released on J-STAGE: December 01, 2022
    JOURNAL RESTRICTED ACCESS

    The Steel Structure Committee of the Japan Society of Civil Engineers established a sub-committee on steel highway steel bridge decks in 1997, which has been conducting ongoing investigations and research since. Sub-committee on Advanced Inspection, Diagnosis and Life-Extending Technologies for Highway Bridge Decks established in 2017 published a compendium of some of the research results titled “Manual for Maintenance of Highway Bridge Decks 2020” (Steel Structure Series 35) in October 2020. This manual focuses exclusively on the maintenance of deck slabs, which are a mong the components of highway bridges that undergo the most deterioration. It is comprised of sections on damage and deterioration of highway bridge decks, inspection and investigation methods, evaluation of deterioration progress and processes, selection of countermeasures, and maintenance case examples. In addition to providing an overview of this manual, this article covers the main revision content, including how to use the manual and the utilization of inspection and assessment technology.

    Download PDF (1184K)
  • N. Onozato
    2021 Volume 59 Issue 12 Pages 991-994
    Published: 2021
    Released on J-STAGE: December 01, 2022
    JOURNAL RESTRICTED ACCESS

    The first edition of “Recommendation for Detailing and Placing of Concrete Reinforcement” was published by the Architectural Institute of Japan forty-two years ago. This year marks the publication of the sixth edition of said Recommendation, which has been newly released as a revision of the previous Recommendation, which came out eleven years ago. This report presents an outline of the Recommendation in the hope that it will be used broadly. Rather than detailing the revisions made in this latest edition, this report presents a simple outline of the Recommendation.

    Download PDF (673K)
  • S. Otsuka, Y. Nakata, S. Sogo, N. Okuyama
    2021 Volume 59 Issue 12 Pages 995-1003
    Published: 2021
    Released on J-STAGE: December 01, 2022
    JOURNAL RESTRICTED ACCESS

    This report presents an overview of the bleeding test method for concrete using small containers (small container method), and summarizes a previous report on an experimental study of factors that may affect the test results of the small container method. As a result of experimental investigation focusing on the containers used for the test, the constituent materials of the concrete, and the mix proportions, it was clarified that the use of containers with diameter (φ) of 125 mm and height (h) of 212.5 mm or φ 150-h 255 allows close approximation of the test results of JIS A 1123. In addition, it was clarified that while the bleeding amount was similar to JIS A 1123 for both containers, the bleeding rate obtained with a container of φ 125-h 212.5 slightly exceeded that of JIS A 1123.

    Download PDF (1797K)
  • Y. Nakata, S. Otsuka, A. Miyata, K. Yoshida
    2021 Volume 59 Issue 12 Pages 1004-1010
    Published: 2021
    Released on J-STAGE: December 01, 2022
    JOURNAL RESTRICTED ACCESS

    This paper describes an attempt to obtain the mechanical efficiency, actual discharge volume, and pressure loss in pipes by comparing the operation records of concrete pumps and the daily work reports recorded by the pumping technicians using the IoT-based fleet management support system operated by a concrete pump manufacturer as a service for users. As a result, it was found that IoT can be used to obtain the mechanical efficiency, actual discharge volume and pressure loss in pipes by comparing the operation records of concrete pumps with the contents of the daily work reports recorded by pumping technicians.

    Download PDF (1364K)
feedback
Top