Haneda Airport (currently known as Tokyo International Airport) was established as Japan’s first national civil airport in 1931. It had a runway 15 m wide and 300 m long on a site of about 53 ha, which was later expanded until it had three runways by 1970. However, with the arrival of jet aircraft and associated enlargement, and then the dawn of the era of mass aviation, there was concern about reaching the limit of the airport’s capacity. This led to plans for an expansion project that would make use of reclaimed land developed by Tokyo Metropolitan Government from a waste disposal site, the so-called Haneda Offshore Expansion Project. The overall project was divided into three phases with a phased opening of the new facilities, since the full budget was not provided initially and there was no way to shorten the construction process.
　The focus of this thesis is the investigation, design and construction of the new Runway C developed as part of the third phase of the expansion project. This third phase of the project was carried out on the extremely soft ground of the former waste disposal site reclaimed from the sea using sludge dredged from Tokyo Bay and waste construction soil. The waste had been dumped on the original seabed, which was a native alluvial clay layer measuring 30 to 40 m in thickness. The requirement was to construct runway C on this ground such that it met strict specifications for evenness. To this end, investigations were carried out to determine a suitable design and construction method for a runway pavement on soft ground with a high groundwater table, to develop a means of recycling material generated by removing existing airport pavements, and to evaluate the pavement after it opened to traffic. Based on this work runway C was constructed and the design method verified.