In March of this year, the Architectural Institute of Japan established the “Recommendations for Demolition Work Reinforced Concrete and Steel Structures”. It is positioned as a revision of the “Recommendations for Demolition Work Reinforced Concrete Buildings” published in 1998. The social landscape has changed since the Recommendations were first published, with the introduction of the Building Recycling Act in 2000 and guidelines for the proper handling and disposal of asbestos, among other things. As a result, the Recommendations no longer reflected existing laws and practices. With the revision of the Construction Business Act in 2014, “Demolition Work” was newly established as a construction work related category in 2016, and the government and industry are working to explore and establish a new framework for such work. Against this backdrop, the present revision marks the first update of the Recommendations in a quarter­century. This paper outlines the main revisions and touches on future tasks.

Various measures have been implemented to address the alkali-silica reaction (ASR), but their inhibitory effects have not necessarily been evaluated quantitatively, and a method to more rationally evaluate ASR-induced expansion is desired. In response, this paper organizes a performance verification-based approach to controlling ASR, and discusses the significance of expansion prediction over time and the importance of improving the reliability of laboratory tests. It also summarizes the results of verification of the effectiveness of the alkali wrapping method, a method developed in Japan to control the problem of alkali leaching in accelerated expansion tests. The results show the tendency of expansion to continue over the long term, which had been overlooked by conventional methods, was observed, and confirmed that stable test conditions were maintained. This method, which provides more reliable expansion behavior, was shown to be useful in clarifying the expansion mechanism and improving the accuracy of expansion prediction.

Evaluation of Classes of Nominal Strength in JIS A 5308 (Ready-mixed Concrete) is reported by required Testing Times and Acceptability Constants of Concrete Strength in Single Sampling Inspection Plans having Desired Operation Characteristics by Variables (JIS Z 9003; Standard Deviation Known). Classes of Nominal Strength in JIS A 5308 may be considered by the reasonable required Testing Times.