## 3 Results and Discussion  
### Assessment of Circular Economy Strategies  
This section presents an integrated analysis of participants' perceptions regarding the importance and feasibility of implementing various CE strategies in the building sector. These strategies are evaluated across four distinct construction project lifecycle phases: design, procurement and construction, operation and maintenance, and end of life. The respondents rated the strategies for importance on a five-point Likert scale ranging from \"(1) not important\" to \"(5) very important\", with rankings determined based on the relative importance index (RII) scores calculated for this. Similarly, the feasibility of implementing these strategies in the Saudi Arabian building sector was assessed using a five-point Likert scale ranging from \"(1) not feasible\" to \"(5) very feasible\", reflecting participants' views on the practicality of adopting these strategies within the sector. This method allowed to prioritize the options, with higher RII scores reflecting higher importance and feasibility for implementation. The RII values are divided into five levels: High (H) (0.8 \(\leq\) RII \(\leq\) 1); High-Medium (H-M) (0.6 \(\leq\) RII \(<\) 0.8); Medium (M) (0.4 \(\leq\) RII \(<\) 0.6); Medium-Low (M-L) (0.2 \(\leq\) RII \(<\) 0.4); and Low (L) (0 \(\leq\) RII \(<\) 0.2) [83]. The analysis of the 15 CE strategies, as shown in Figure 3 and based on the mean scores of a five-point Likert scale, reveals significant insights into their perceived importance and feasibility for implementation across various project lifecycle phases. In addition, Tables 4 and 5 present the detailed results concerning the respondents' views on the importance and feasibility of the 15 CE strategies included in the study. \begin{table}
\begin{tabular}{c c c c c c c c c c c c c c c c c} \hline \hline \multirow{2}{*}{**Project Phase**} & \multirow{2}{*}{**CE Strategy**} & \multicolumn{8}{c}{**Participant Responses**} & \multirow{2}{*}{**Mean**} & \multirow{2}{*}{**RII**} & \multirow{2}{*}{**Rank**} & \multicolumn{2}{c}{**Importance**} \\ \cline{3-14}  & & **A1** & **A2** & **C1** & **C2** & **C3** & **CN1** & **CN2** & **CT1** & **CT2** & **D1** & & \\ \hline \multirow{4}{*}{Design for Deconstration/Dissassembly} & 5 & 5 & 5 & 5 & 5 & 5 & 4 & 5 & 4 & 5 & 4.80 & 0.96 & 2 & High \\ \cline{2-14}  & Design for Adaptability and Flexibility & 5 & 5 & 5 & 4 & 5 & 5 & 3 & 5 & 3 & 5 & 4.50 & 0.90 & 7 & High \\ \cline{2-14}  & Design for Standardization. & 5 & 4 & 4 & 5 & 4 & 4 & 2 & 4 & 2 & 4 & 3.80 & 0.76 & 11 & High-Medium \\ \cline{2-14}  & Design for Durability and Longevity & 5 & 2 & 5 & 5 & 4 & 5 & 5 & 5 & 5 & 4.60 & 0.92 & 6 & High \\ \cline{2-14}  & Design for Modularity & 4 & 3 & 4 & 4 & 5 & 3 & 3 & 4 & 3 & 4 & 3.70 & 0.74 & 13 & High-Medium \\ \cline{2-14}  & Predabrication and Offsite Construction. & 4 & 2 & 4 & 4 & 4 & 4 & 4 & 5 & 3 & 4 & 3.80 & 0.76 & 11 & High-Medium \\ \cline{2-14}  & Procuring Reused and Recycled Materials. & 5 & 5 & 4 & 4 & 5 & 5 & 5 & 5 & 5 & 5 & 4.80 & 0.96 & 2 & High \\ \cline{2-14}  & Procuring Bio-based Materials. & 3 & 4 & 4 & 4 & 5 & 3 & 4 & 3 & 4 & 3 & 3.70 & 0.74 & 13 & High-Medium \\ \cline{2-14}  & Renewable Energy Integration. & 5 & 4 & 5 & 5 & 5 & 5 & 4 & 5 & 5 & 5 & 4.80 & 0.96 & 2 & High \\ \cline{2-14}  & Maintenance & Adaptive Reuse. & 4 & 5 & 5 & 4 & 5 & 4 & 5 & 5 & 5 & 4.70 & 0.94 & 5 & High \\ \hline \multirow{4}{*}{End of Life} & Reuse of Materials and Products. & 5 & 5 & 5 & 4 & 5 & 5 & 5 & 5 & 5 & 4.90 & 0.98 & 1 & High \\ \cline{2-14}  & Closed-Loop Recycling (up-cycling). & 5 & 5 & 4 & 4 & 5 & 4 & 5 & 4 & 4 & 4.50 & 0.90 & 7 & High \\ \cline{2-14}  & Open-Loop Recycling (down-cycling). & 3 & 3 & 3 & 4 & 5 & 4 & 4 & 3 & 4 & 3.60 & 0.72 & 15 & High-Medium \\ \cline{2-14}  & Selective Demolition. & 5 & 3 & 4 & 3 & 5 & 4 & 4 & 4 & 3 & 4 & 3.90 & 0.78 & 10 & High-Medium \\ \cline{2-14}  & Deconstruction. & 5 & 4 & 4 & 4 & 5 & 4 & 4 & 5 & 3 & 5 & 4.30 & 0.86 & 9 & High \\ \hline \hline \end{tabular}
\end{table}