## 4 Computational Experiments
### Summary of Results and Managerial Insights  
The comparison between our two-stage stochastic model and the mean value model for the planning of establishing recycling centers shows that our model achieves a higher recycling rate. The sensitivity of the optimal recycling rate of construction waste to total disposal costs provides crucial insights for the government, which allows them to optimize the locations and sizing of recycling centers based on investment levels.  
First, the uncertainty associated with the generation and demand of construction waste significantly influences waste management strategies. Failure to reckon with these uncertainties may lead to decision makers devising suboptimal plans, resulting in inefficient investment usage and limited material recycling efforts. Notably, when managed with a total expenditure of 886 million CNY, the two-stage stochastic model enables the recycling of over 32,110 tons more construction waste than the mean value method.  
Second, the sensitivity analysis emphasizes the cost-effectiveness of constructing a recycling center for construction waste as compared to direct landfill disposal, provided that proper site planning is implemented. Additionally, computational models reveal that if construction waste is solely disposed of via landfill, the associated cost would amount to approximately 886 million CNY. Conversely, an initial investment of the same magnitude can achieve a recycling rate of 31.90%. This clearly suggests that some recycling facilities are already operational, and further reductions in investment do not preclude recycling endeavors. The recycling centers built are in locations with convenient access to construction sites, which indirectly emphasizes the importance of transportation costs. Thus, these facilities are well-planned, as evidently, the cost of recycling construction waste proves lower than disposing of it in a landfill.  
Third, an examination of investment variability reveals rapid changes in recycling rates occurring between 800 and 900 million CNY. This observation demonstrates a clear positive correlation between increased financial investment in waste management and enhanced recycling efficacy. Consequently, it is imperative for decision makers to thoroughly consider recycling objectives and adjust budget allocations accordingly to optimize outcomes in waste management strategies.  
When the total investment surpasses a certain threshold, additional increments do not augment the volume of construction waste recycled. This plateau indicates that the capacity of the planned recycling centers has been maximized. Under the circumstances of an ample budget, the planning of additional recycling centers should be considered. This rate plateau is visually represented by a horizontal dashed line extending from the point where the maximum recycling rate begins to where it first occurs, delineating the fact that beyond the threshold, additional investment does not result in improved recycling rates. Decision makers are encouraged to consider the establishment of additional recycling facilities once the budget exceeds this established threshold.