Sustainability: A Role for Blended Cements and Industrial Byproducts in Soil Mixing, Grouting, and Slurry Walls-Paper

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The paper argues that deep soil mixing, subsurface grouting, and slurry walls can be made more sustainable by replacing some ordinary Portland cement (OPC) with blended hydraulic cements (BHCs) or industrial byproducts, especially ground granulated blast furnace slag (GGBFS). These materials can reduce reliance on virgin resources and lower the environmental impacts associated with cement production.<br /><br />Life Cycle Assessments (LCAs), reported through Environmental Product Declarations (EPDs), provide a basis for comparing cement impacts. The paper’s example data show global warming potential of 1,040 kg CO₂-equivalent per metric ton for OPC, 892 for BHC, and 147 for slag cement. Slag cement also has lower reported impacts for energy use, non-renewable resource consumption, and several other indicators. Comparisons require care because EPD boundaries and product-category rules may differ, and the relevant supplier should be represented in the EPD.<br /><br />Project teams can estimate a mix’s impacts using the proportions and EPD data for its components. Mixes must still meet performance specifications; optimization with slag or other supplementary materials may also reduce the total amount of cementitious material required. Cost and material availability remain practical considerations.<br /><br />Project examples illustrate potential benefits. At the Jade Signature condominium in Florida, deep soil mixing used a mix of approximately 85% slag cement and 15% OPC. The paper estimates that this mix, compared with an equal quantity of OPC, avoided about 10,500 metric tons of CO₂ emissions. At the Herbert Hoover Dike, slag cement was used in cutoff walls to meet permeability requirements, with estimated reductions in emissions, energy use, and freshwater consumption compared with OPC.<br /><br />The authors conclude that EPD-supported material selection can help geotechnical projects reduce environmental impacts and potentially support sustainability and LEED objectives.

Keywords

deep soil mixing

subsurface grouting

slurry walls

ordinary portland cement

blended hydraulic cements

ground granulated blast furnace slag

life cycle assessment

environmental product declarations

carbon emissions reduction

sustainable geotechnical engineering