THE STATE OF USING BY-PRODUCTS IN CONCRETE IN JAPAN AND OUTLINE OF JIS/TR ON “RECYCLED CONCRETE USING RECYCLED AGGREGATE”
Hir otak a K A WA NO Public Works Research Institute, JAPAN
Keywords: by-products, recycle, recycled aggregate, recycled concrete,
In the last few decades much research and development has been conducted on the reuse of many kinds of by-products in concrete and many papers have been published every year. However, although large quantities of several kinds of by-product materials are used in concrete today, the reuse of many kinds of by-products has not grown in spite of intensive research and development. This paper outlines the state of reuse of by-products in concrete in Japan and outlines the problems related to reuse. It also summarizes the JIS Technical Report, TR A 0006 “Recycled Concrete Using Recycled Aggregate” published in 2000.
2. PURPOSE OF RECYCLING
Papers relating to recycling in the concrete industry usually define the purposes of the research to be saving resources and energy, rational use of materials, and sustainable use of materials. Some papers also mention zero-emissions and building a closed cycle of materials usage. These are all important keywords today. The current usage and research and development on the reuse of by-products related to concrete can be classified into the following three categories: - Category 1: Use of by-products, from non-construction industries to concrete - Category 2: Use of by-products, from concrete to concrete - Category 3: Use of by-products, from concrete to other materials Before looking at the situation in Japan, we consider the purpose of reuse. The ultimate purpose of recycling materials is to minimize the impact of human activities on the environment and the planet. From this viewpoint, the first priority of concrete engineers is to maximize the lifespan of concrete structures, at least concerning Category 2, because buildings and...