Estimating Sustainability Benefits from Use of Blended Cements and Slag Cement at Geotechnical Projects

Abstract

Portland cement, blended hydraulic cement, and slag cement are all cementitious materials used in deep soil mixing, subsurface grouting, and slurry walls. Portland cement is the “default” cementitious material used in geotechnical applications due to its known properties and history of good performance. Production of portland cement results in life cycle impacts. Blended hydraulic cement and slag cement are composed of industrial byproducts. Much of life cycle impact of these industrial byproducts has already been borne by the industries that generated them. Life Cycle Assessments are a means to quantify life cycle impacts and can be used to compare the relative life cycle impacts of one cementitious material or mix design to another. Owners, engineers and contractors can contribute to the sustainability of a geotechnical project by increasing the use of blended hydraulic cements and slag cement in geotechnical projects while attaining the project’s performance standards. Two case studies are presented that demonstrate the sustainability impacts of different cement mixtures. Sustainability contributions may competitively position a proposed geotechnical application or cementitious material mix design against less sustainable proposals.