A Simplified Circularity Assessment Model for Soil Mixing Applications-Paper

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The paper presents a simplified circularity assessment model to help soil-mixing teams reduce embodied carbon and support a circular economy. Because cement and diesel account for most emissions from soil mixing, the model emphasizes collaboration among owners, engineers, contractors, suppliers, regulators, and site teams across design, procurement, construction, quality control, and future reuse.<br /><br />The model’s technical and operational pathways include reducing project scope, selecting lower-carbon materials, improving equipment and processes, using renewable energy and fuels, and minimizing waste. Quality control is essential to verify performance, prevent rework, and avoid unnecessary material use.<br /><br />Case studies illustrate the potential benefits. Design changes and a cement blend containing slag reduced embodied carbon by about 4,200 tonnes. Applying a 90-day strength criterion reduced cement use by 10% on one project. Alternative binders, including slag and ground-glass pozzolan, cut grout emissions by 42–54%; field and laboratory trials also achieved cement reductions of up to 30–40%. Adjusting grout fluidity increased production by up to 40%, potentially saving more than 82,000 liters of diesel. Renewable diesel and Type IL cement provided additional project-specific emissions reductions. Predrilled cavities reduced excess soilcrete and cement consumption by 10–30%.<br /><br />The paper also highlights soil mixing’s role in rehabilitating existing infrastructure, avoiding carbon-intensive replacement. Future projects may reuse existing soilcrete elements, provided their condition and capacity are verified through records, coring, strength testing, pressuremeter testing, or other appropriate methods. The authors stress that careful documentation and planning for future access can make reuse more practical.<br /><br />Overall, the model offers a framework for tracking and implementing innovations that make soil mixing more efficient, cost-effective, lower-carbon, and compatible with circular resource use.

Keywords

soil mixing

embodied carbon

circular economy

cement reduction

diesel emissions

alternative binders

quality control

soilcrete reuse

lower-carbon materials

renewable diesel