Life-Cycle Cost Comparison of Cement Concrete and Polymer Concrete Manholes Used in Sewer Systems

Due to the high vulnerability of the concrete manholes to chemical corrosion, requiring a need for frequent maintenance and replacement, polymer concrete manholes are used as a substitute in water and wastewater pipelines. Polymer concrete manholes have a longer service life and more resistance to various chemical corrosives than normal concrete manholes. Despite the benefits from using polymer concrete manholes, the higher initial capital cost has been a barrier to wider application in public works. In this study, data was collected for the initial installation costs and replacement frequency to compare the life cycle costs for both types of manholes. The data was collected from the Clark County Water Reclamation District, the public entity responsible for constructing sewer pipelines in the Clark County. The scope of the cost analysis was limited to the initial capital cost of these two types of manholes used in sewer systems. An initial capital cost data (material, equipment, labor) and as well as replacement frequency data for both types of manholes were analyzed. The results showed that the life-cycle installation cost of polymer concrete manholes was significantly less than that of cement concrete manholes for this sample based on 50 years life cycle period. However, due to lack of data, a comprehensive life-cycle cost analysis of cement concrete manholes could not be conducted. The findings of this study will help water and wastewater engineers to identify the cost effectiveness of these two types of manholes.