Alternative Binder for Ground Improvement to Reduce Co2 Footprint-Paper

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The Sandbukta–Moss–Såstad (SMS) railway project in Norway required ground improvement in quick clay before excavation and construction. Dry soil mixing (DSM) was selected, with an initial design calling for about 25,000 tonnes of binder at 90 kg/m³.<br /><br />A test field compared Standard cement with Multicem, a binder made mainly from Portland cement and cement kiln dust (CKD), at application rates of 40, 60 and 90 kg/m³. Column strength was assessed using FOPS and FKPS penetration tests. Standard-cement columns proved too resistant for the testing equipment to assess their full length. Multicem columns were successfully tested and achieved the required average design shear strength of 200 kPa. Results showed a substantial strength increase from 40 to 60 kg/m³, but little additional increase at 90 kg/m³. Laboratory tests also indicated that strength continued to develop after the early field tests.<br /><br />Based on the test results, the project adopted Multicem at 40 kg/m³. This reduced binder use from 25,000 to 11,100 tonnes— a saving of 13,900 tonnes—and cut estimated CO₂ emissions from 15,100 to 8,950 tonnes, a reduction of 6,150 tonnes. The study highlights how field testing alternative binders and optimizing dosage can reduce environmental impacts. It also notes that high DSM strengths can exceed the capacity of conventional FOPS and FKPS testing equipment, suggesting a need for alternative testing methods or lower, better-targeted binder dosages.

Keywords

Sandbukta-Moss-Såstad

Norway

dry soil mixing

quick clay

Multicem

Portland cement

cement kiln dust

ground improvement

shear strength

CO2 reduction