Asset management is a strategic decision-making aspect of social infrastructure that ensures safety by predicting long-term conditions and maximizing effectiveness under budgetary constraints. Predicting the deterioration of impervious walls is essential in the asset management of coastal landfill sites, particularly in the design of their maintenance and repair strategy. In this paper, a quantitative evaluation of the leakage of toxic substances in coastal landfill sites where deterioration of side impervious walls has decreased the water interception performance is reported. In addition, risk evaluation based on the asset management of the leakage is applied to determine an appropriate repair method. The strategy of repairing the walls when the concentration of the toxic substances leaking into the sea area exceeds the closure and abandonment of coastal landfill sites is demonstrated to be superior. Moreover, the strategy of repairing only the seaside side impervious wall is shown to be cost-effective.

In late years, quantity of construction by-products tends to increase in our country. Therefore, dumping restraint of construction by-products and promote those recycling are the most critical issue from a viewpoint of establishing the recycling society. In the other hand, soils generated from construction generally show strong alkalinity because cements are mixed. Thus, the cost at the time of the disposal of soils generated from construction becomes expensive, and it is thought that it has a great influence on environment when the soils is disposed by no improvement. However, it is the present conditions that technique in consideration of the influence on environment with non-appropriate processing is not established. Therefore, a vegetation is applied for an index indicating a recycling potential of soils generated from construction. This paper is inspected experimentally to the potential of soils generated from construction as a planting base by mixing neutralizing agents. It was realized that the soils generated from construction had vegetation by mixing neutralizing agents.