Development and Practicability Study on Methods for Assessing Environmental Impact of Concrete

本研究的目的是开发一种混凝土环境影响的评价方法，其中有效利用资源和可持续发展的行动在经济方面变得可行。本研究探讨了混凝土材料评价体系的建立和混凝土环境影响评价方法的建议，在材料评价体系的建立中，研究了混凝土中重金属浸出对环境影响的影响。结果发现，目前的批量测试中，样品被造粒的重金属浸出不适合从混凝土结构的重金属浸出的长期行为的预测。根据混凝土结构的长期环境影响评价方法，提出了两种评价混凝土结构环境影响的方法。在清单数据方面，编制了与混凝土结构的材料制造、建造、拆除、处置和再利用有关的91个项目，涉及能源、矿产资源（非金属和铁）和能源资源（煤、石油和天然气）的消耗，CO_2、NO_x、SO_x和粉尘的排放以及废物的使用和排放。基于性能化设计理念，提出了验证环境性能的评价方法和考虑环境性能的评价方法。在这两种方法中，混凝土结构在生命周期中的环境影响程度被定义为环境性能。由于这些方法包含了环境影响因素的综合，并考虑了建设成本的影响，因此应该具有足够的实用性。

The aim of this study is to develop an evaluation method of environmental impact of concrete in which an action toward effective uses of resources and sustainable development becomes practicable in terms of economical aspects. The development of an evaluation system of materials for concrete and the proposal of methods for evaluating environmental impact of concrete were discussed in this study.In the development of an evaluation system of materials, the effects of heavy metal leaching from concrete on environmental impact was investigated. As a result, it was found that current batch tests of heavy metal leaching in which samples were granulated were not suitable for the prediction of long-term behavior of heavy metal leaching from concrete structures. Analytical evaluation of long-term heavy metal leaching from concrete structures will be much better using the apparent diffusion coefficient of heavy metal in concrete which can be estimated from the results of the tank leaching tests.After the preparation of inventory data, two kinds of methods for evaluating environmental impact of concrete structures were proposed. For inventory data, 91 items associated with material manufacture, construction, demolishment, disposal and reuse of concrete structures have been prepared regarding the consumptions of energy, mineral resources (non-metallic and ferric) and energy resources (coal, oil and natural gas), the emissions of CO_2, NO_x, SO_x and dusts and the use and emission of wastes. In terms of the performance-based design concept, an evaluation method verifying environmental performance and an evaluation method considering environmental performance were proposed. In both methods, the degree of environmental impact in the life cycle of concrete structures was defined as environmental performance. Since these methods include the integration of environmental impact factors and consider the effect of construction cost, they should be sufficiently practical.