This article provides an overview of the revisions implemented in the JSCE Standard Specifications for Concrete Structures ─Maintenance─ published by the Japan Society of Civil Engineers in 2022. This revision augments the matter related to performance evaluation and adds a new chapter dedicated to actions on the structures. The objective of regular inspections has been slightly modified. A new classification has been applied to countermeasures. Further, the latest technology has been reflected. This includes the addition of a new chapter on complex deterioration. The revision work was carried out keeping in mind that the majority of readers are the engineers involved in maintenance, and thus emphasis was placed on making the content of the Standard Specifications easier to use by slimming down the［ Standard Methods］part, etc.

A large scale casting experiment was conducted to investigate the applicability of mechanically compacted flowable concrete, an item that was newly added in the 2019 revision of JIS A 5308 “Ready-mixed concrete”, to port concrete structures, and to understand its effects on construction quality and productivity improvement at construction sites. Through a comparison based on visual inspection of the exterior and cut faces, as well as the results from ultrasonic wave propagation velocity measurements, it was confirmed that the quality of construction using mechanically compacted flowable concrete is at least on par with that of construction using ordinary concrete managed by slump. Regarding productivity improvement, it was confirmed that vibrator operation time and the travel distance of the vibrator operator were significantly reduced, and that the same or better construction quality can be ensured with a smaller labor load, suggesting the possibility of making a significant contribution to productivity improvement at construction sites.

Polypropylene short fibers are used for the purpose of inhibiting the propagation of cracks in concrete. Polypropylene short fibers bridge cracks and control the propagation of cracks. For non-structural members of architectural structures such as concrete slab-on-grade, it is possible to fabricate members solely with polypropylene short fiber reinforced concrete, eliminating the use of reinforcing bars and wire mesh for controlling the progression of drying shrinkage cracks. The elimination of rebar installation work (process) not only shortens the construction period but also removes a workplace tripping hazard, improving work efficiency and contributing to higher productivity at construction sites.