An Advanced Concrete Recycling Technology and its Applicability Assessment by the Input-Output Analysis

Hirokazu Shima, Hisashi Tateyashiki, Ryuji Matsuhashi and Yoshikuni Yoshida

Journal of Advanced Concrete Technology, 3(1) 53-67, 2005

While at present mostly recycled into road subbase, the amount of demolished concrete in Japan is expected to increase rapidly and exceed the demand of road subbase in the near future. To promote the recycling of concrete, a technology to produce high-quality recycled aggregate has been developed. This technology employs the heating and rubbing method. In order to investigate a future concrete recycling system, first of all, a specific model considering indices of economic activity is established to forecast the amount of demolished concrete in the future. Furthermore, an input-output table is extended by a detailed description of concrete-related industries such as construction, aggregate, cement, and ready-mixed concrete, and several concrete recycling processes have been added.The linear programming model connected to the input-output table assumes that the technology to be introduced in 2020. A subsidy for the high-quality recycled aggregate and a carbon tax are found to be effective to the early introduction of the technology.

The paper is impressive in its comprehensive approach which quantifies technological aspects, environmental aspects and economic ones. When dealing with environmental issues there is a trend to deal with concepts. This paper deals with the concepts as well as their very comprehensive quantifications, and as such it is unique. (Prof. A. Bentur, Technion, Israel)