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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.

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City is the main place to consume goods and services throughout the world. Among the various consumption terminals, household-level consumption is highly behavior driven, which can be affected by various factors such as household income level, age, living environment etc. However, city-level household emissions characteristics are still not fully understood due to the complexity of consumption behaviors and the lack of the supply chain's data. To include the environmental responsibility embodied in residential consumption and reveal the how it varies among household type and season, this study investigated city-level household consumption as it relates to energy demand using a cityscale input-output model and urban residential consumption inventories. Importantly, age-and monthbased emission are analyzed from different aspects such as emission type, source, fuel types and consumption items. Findings indicate that 1) household emissions differ substantially among the various household age groups; older households generally produce higher emissions levels on a per 1 The short version of the paper was presented at CUE2018, Jun 5-7, Shanghai, China. This paper is a substantial extension of the short version of the conference paper. 2 capita basis; 2) decreases in temperature are the main reason for the increased emissions in older households, while this is not a significant factor in younger households; 3) the high per capita household emissions in older households indicate inefficient energy usage among elder citizens, which strongly suggests that aging societies will face long-term emissions increases if appropriate measures are not taken.

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