The paper investigates the second-order interactions of parameters in an alkali-activated mixture of paper production waste (PPW) and blast furnace slag (BFS) in Taguchi method. The PPW including lime mud (LM) and paper sludge (PS). This paper provides the experimental models to assess the compressive and flexural strength of them at 7-day and 28-day. The results have shown that the second-order interactions between PPW and alkali-activated activator exists in each experimental model, and the significant interactions affect the selection of optimal compositions. Compared with the interactions between the PPW themselves, the interactions between PPW and alkali-activated parameters are the main significant factors affecting its physical properties. In each experimental model, the maximum compressive strength was 47.41 MPa in 7-day and 65.64 MPa in 28-day. Compared with the confirmatory experiments, the deviation of prediction calculated by experimental models was 3.08% and 0.56%, respectively. The maximum flexural strength was 5.74 MPa in 7-day and 5.96 MPa in 28-day; compared with the confirmatory experiments, the deviation of prediction calculated by experimental models was 5.40% and 0.17%. Considering the influence of circular materials, 30% of PPW should be a suitable ratio to replace BFS as the raw material of alkali-activated slag (AAS).

After natural resources are mined, they are stored in cities in the form of urban minerals through the construction of buildings. However, buildings have many negative impacts on nature from the time they are constructed and used to the end of their life cycles when they are demolished and discarded. At present, many researchers have conducted research on the recycling of buildings, including the whole life cycle of buildings, the value assessment of the construction waste, the recycling boundary of the construction waste, and the way building waste could be reused. These studies all need to discuss the types of construction waste and their total volume. Urban mining uses GIS data (top-down) and the same type of building material per unit area (bottom-up) to provide a broad calculation method for the construction waste, but it fails to accurately obtain the exact amount of each material of the building. From the perspective of architectural design, the same type of buildings tend to have different spaces and structures due to factors such as the site, orientation, and function. These all affect the way construction waste is reused. This paper aims to create a framework for the reuse of construction waste to improve the accuracy and diversity of the reuse of construction waste in the future. The main purpose of this article is to provide a more accurate assessment of the material which is contained in a building. Using a 48-year-old office building in the Taiwan Contemporary Culture Laboratory (TCCLab) as the research case study, the paper compares the data calculated by different methods and verifies the difference between the bottom-up and the disassembly classification method proposed in this study. According to the architectural design principles, the authors first carried out a 3D digital modeling of the office building (including the building structure) using a forward construction sequence and then they proposed the framework of the material classification and the reuse of the reinforced concrete (RC) of the office building using the method of reverse disassembly, hoping to provide a reference for the reuse of construction waste.

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Waste recycling has always been a priority in the paper industry. In this study, the potential of translating various wastes in papermaking into building materials was separately evaluated. For the first time, the improvement of flexibility and sample texture after translating wastes into cementitious materials was analyzed. The results showed that 20% of the waste in alkali-activated slag slurry is the best proportion for papermaking. In addition, paper sludge and wood chips significantly improved the slurry flexibility while lime mud and bottom ash did not have this effect. Considering the effect of adding wood chips on the optimization of the sample texture, the most appropriate proportion of the paper sludge was 5% when the wood chips in the mixture were 15%. The most suitable alkali equivalent was 6%, with a silicate modulus of 0.9. According to the experimental results, wastes in papermaking had great potential for exploitation and application as circular materials.

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