ライフサイクルにおける土木構造物の環境負荷評価
地球規模の環境問題に対する意識が向上し，土木構造物についてもライフサイクルを考慮した環境影響評価（以下LCA）が求められている。LCAやその統合化手法は土木構造物に関わる環境保全・改善の検討に有効であるが，これらの手法は工業製品を対象に開発されたため，土木構造物に適用する場合には課題が残されている。著者らは新しい技術を適用した土木構造物や土木工事に関するLCAを行ってきた。これらの事例で生じた問題点や，新規技術の優位性を適切に評価するという観点から，現状のLCAに関する課題等について検討した。工事期間中の環境改善効果を評価する手法の必要性や重要性，個別生産される建設機械のインベントリデータの取得方法や汎用機器の稼働率の予測方法など土木構造物の特殊性を鑑みたデータの整備，統合化手法における検討事例の追加の必要性などを指摘した。
| キーワード： | LCA，CO2排出量，温暖化ガス，環境負荷，統合評価 |
＊１ 技術センター 土木技術研究所 水域・環境研究室
＊２ 技術センター 土木技術研究所 土木構工法研究室
Life Cycle Assessment of Civil Engineering Infrastructures
In the wake of increased recognition of the importance of global environmental issues, a great need has arisen for life-cycle assessments (LCA) of civil engineering infrastructures. While the LCA and its integrated method are effective for planning the preservation and improvement of environments associated with civil engineering works, these methodologies were developed originally for dealing with manufactured industrial products. Thus, several gaps remain when these methods are applied to civil engineering infrastructures. Under such circumstances, the authors have examined construction projects that employed new technologies from the LCA point of view. In the course of this study several problems and suggestions were pointed out in order to properly evaluate superiority of new techniques in reviewing of those LCAs. It was pointed out that the development and/or improvement of following items are necessary;
- a technique to evaluate effects of environmental improvement during a construction stage,
- an acquisition method of the inventory data of a construction machine produced individually,
- an estimation method of rates of operation of general-purpose machineries,
- an improvement of the database about inventory data which considered the characteristic of civil - engineering infrastructures,
- an accumulation of examination by the integration of impact assessment to understand the feature of each method.
| Keywords: | LCA, CO2 emissions, greenhouse gases, environmental load, impact assessment |
*1 Hydraulic and Environmental Engineering Research Section, Civil Engineering Research Institute, Technology Center
*2 Civil Structure and Material Research Section, Civil Engineering Research Institute, Technology Center
