## 2 Literature Review and Hypothesis Development
### Sustainable Use of Construction Material (SUCM)  
The implication of sustainability is broad, including dimensions of environmental, economic, social, cities, development, construction, etc. [50]. Various tools have been developed and adapted in the construction field to assess sustainability from different perspectives and for a variety of users. The life cycle assessment (LCA) established by the European Union (EU) is widely used to evaluate the environmental performance of construction products and processes [7; 51; 52]. However, the building process is less standardized than other mature industrial processes--e.g., manufacturing industry--and quantitative information about the environmental impacts of the production and manufacturing of construction materials is limited [53; 54]. Therefore, conducting an efficient LCA in the construction industry is still a challenging task.  
[PERSON] et al. summarized two ways of applying LCA for the building material and component combinations (BMCC) and the whole process of the construction (WPC) [55]. This paper focuses on exploring the impact of CSCI on the BMCCs rather than WPC, which has a broader scope. Environmental product declarations (EPD) is a strategy adopted for reducing the environmental impact of BMCCs, while Green Public Procurement (GPP) is developed to improve construction procurement especially for the public sector [7; 55]. Additionally, several tools have been developed specifically for the construction sector such as Leadership in Energy & Environmental Design Building Rating System (LEED), which provides measurement ratings for green buildings [54]. LEED and the other guidelines such as Waste Framework Directive (WFD) provided by the EU address C&D waste management [7].  
Along with the above policies and standards, a literature review is conducted to identify indicators to assess the sustainable use of construction materials, from raw material extraction to production, consumption, and finally, waste treatment. Some literature presented case studies--e.g., recycled aggregate as a sustainable construction material [6]--while others explored critical factors contributing to sustainability in construction materials [56]. As shown in Table 2, a total of nine factors of sustainable use of construction material are extracted from the literature and sorted into three groups. BMCC environmental design and C&D waste sustainable treatment are coded as BED and CST.  
\begin{table}
\begin{tabular}{c l c} \hline \hline
**Code** & **Form/Item** & **Reference** \\ \hline
**BI** & Backward integration & \\ bi\_1 & Source control & \\ bi\_2 & Bring influence to the off-site process & [16; 41] \\ bi\_3 & Off-site process monitoring & \\ bi\_4 & Transfer partial on-site activities into off-site, e.g., prefabrication & \\ \hline
**FI** & Forward integration & \\ fi\_1 & Acceptance of ideas proposed by clients or end-users & \\ fi\_2 & Improvement based on ideas from clients or end-users & [47; 49] \\ fi\_3 & Joint decision-making & \\ fi\_4 & Joint decision-driven implementation & \\ \hline
**RL** & Reverse logistics & \\ rl\_1 & Purchase permit of recycled materials & [18; 48] \\ rl\_2 & Recycle C\&D waste to the secondary market & \\ rl\_3 & Recycle C\&D waste to the raw material market & \\ \hline \hline \end{tabular}
\end{table}
Table 1: Components of CSCI.  
Table 2 also shows the frequency the literature mentioned of each factor to indicate the attention it has attracted. These factors are hypothesized to be critical in improving sustainable performance in construction material extraction, production, consumption, and waste treatment.