Pavement work in the Yanagawa Tunnel on National Route 107 (tentative name)

Length = 1,074 m, Width of pavement : 7.16 m

Concrete pavement work : 7,410 m², Roadside ditch construction : 2,054 m, Roadside curbstone : 2,046 m, Pavement markings drawing : 2,940 m

Construction assessment score: 96 points
The project site was the Yanagawa Kuchinai Tunnel, which connects Esashi Yanagawa in Oshu City to Kuchinai in Kitakami City along National Route No. 107. This tunnel was being constructed by Iwate Prefecture as part of a disaster restoration support road. The project included concrete pavement work inside the tunnel. To meet the deadline for the road’s opening, the project needed to focus on effective process management and maintaining concrete quality in cold weather conditions. The project implemented various ideas as follows. (1) The construction period was reduced by assessing the subgrade using small-type FWD testing rather than the conventional plate loading test. (2) To achieve a broom finish on the pavement surface, a rough surface finishing machine was used to ensure uniform finish quality and reduce labor. (3) A penetrating surface curing compound was applied for the concrete curing process. Additionally, balloons were placed at the tunnel openings to shield against wind and snow, preventing early-stage freezing damage and cracks in the concrete. (4) A highly penetrating asphalt emulsion (PK-P) was applied as a prime coat to enhance permeability and reduce tire adhesion. (5) Oxygen concentration and the presence of combustible gas were monitored upon entering the tunnel and during construction to assess the work environment and ensure worker safety. Additionally, activities contributing to the local community were actively pursued. Because of the effects of related construction projects, the start of this project was set to September. Additionally, five different projects were concurrently underway in the tunnel or nearby areas. Therefore, a Construction Implementation Council was established to facilitate the smooth progress of these projects. The project’s commitment to maintaining quality, adhering to the client’s schedule requirements without accidents, and completing the project successfully ahead of schedule received high praise.