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

While at present mostly recycled into road subbase, the amount of demolished concrete in Japan is expected to increase rapidly and exceed the demand for 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 will be introduced in 2020. A subsidy for high-quality recycled aggregate and a carbon tax are found to be effective ways to promote the early introduction of the technology. This series of analysis can be widely used in other countries for investigating suitable recycling systems focusing on the cement and concrete industry as well as the applicability of each individual concrete recycling technology.