Concrete hydrodemolition and diamond grinding/grooving operations performed for the North Carolina Department of Transportation (NCDOT) generate large amounts of concrete residuals. Currently these residuals can be classified by the North Carolina Department of Water Resources (NCDWR) as Class A Residuals and are treated as “inert debris” thus allowing them to be reused instead of being disposed at Publicly Owned Treatment Works (POTW) and Municipal Solid Waste (MSW) sites. A Benefit-Cost analysis is needed in order to investigate potential savings from other alternative options to disposal such as the use of the material as liming amendments on NCDOT right of way highways, Class B residual sites and agricultural applications. These alternative methods of disposal need to satisfy current federal guidelines and state regulations and contractors disposing of the concrete residual materials need to be aware of these regulations as well.
The objectives of this project will be to provide NCDOT with a Benefit-Cost Model (BCM) using Multi-Criteria Analysis that would enable the estimation of the costs of disposing and/or reusing concrete residual material that is produced by the hydrodemolition and diamond grinding/grooving processes. In addition to the BCM, a tool will be developed that can be used by contractors undertaking such projects to better estimate their costs and to allow them to compare alternatives for the disposal/reuse of the concrete residual material. The researchers will also develop a risk analysis for the comparison of several feasible alternatives to disposal of concrete residuals, a tool for contractors to use to estimate their anticipated costs for disposal or reuse of concrete particulars, and recommendations on acceptable methods for handling concrete residuals after monetary, environmental factors and risk have been considered. Recommendations for guidelines and/or specifications that could be provided to contractors for use on future NCDOT projects will be provided.
As part of this work the researchers will use literature and case studies to identify the best practices for the disposal/reuse of the concrete residual material both from North Carolina and other states. By surveying DOT personnel and contractors identify the attributes that contribute to the costs of the various alternatives. Using these attributes the BCM will be developed and eventually tested on NCDOT projects selected to serve as case studies. These case studies will allow the model to be refined to be accurately implemented on future NCDOT projects. This project will directly support the sustainability and safety initiatives mandated by the MAP-21 legislation.
