Sustainability Assessment of Controlled Low Strength Materials Utilizing Various Industrial Waste Materials

Controlled low strength material (CLSM) can be used as backfill material for utility trench construction. Many researchers proposed CLSM using industrial waste materials as part of the designs of these cementitious mixes. In this study, a comparative sustainability assessment of different CLSM designs that incorporate industrial byproducts is performed and compared to a conventional aggregate backfill design. This study also assessed the comparative sustainability of CLSM and conventional aggregate as trench backfill for a utility pipe installation on a roadway/drainage improvement project. The project includes 1.5 miles of utility trenching of a proposed frontage road and drainage improvement in the Chicago metropolitan area. The sustainability assessments include evaluating the environmental, economic, and social (triple bottom line) impacts of the alternate CLSM and conventional trench backfill options. A single sustainability index for each backfill design is computed using a multi-criteria decision analysis methodology and compared to identify the most sustainable CLSM design option.