Improving the remoulded shear strength of a quick clay using biochar
Improving the remoulded shear strength of a quick clay using biochar
In the pursuit of finding a less carbon-intensive binder alternative to cement, an ongoing research project in Norway is investigating the effect on properties of various soft soils when substituting parts of the cement with industrial by-products and biochars. This paper considers how three biochars influence the soil properties of a Norwegian quick clay when acting as the only binder. The practical application would first and foremost be to ease the handling and transportation of excavated quick clay by increasing its remoulded shear strength. The laboratory study determined that the biochar that yielded the lowest shear strength when added alongside cement had the distinctly largest positive influence when added alone. At a quantity of 100 kg/m3, this particular biochar, made from calcinated sewer sludge, increased the fall cone shear strength of the remoulded clay from an average of 2.3 kPa to 85.0 kPa after 28 days of storage, and to above 100 kPa after 90 days. The follow-up unconfined compression tests only revealed shear strengths of 19.5-31.4 kPa, indicating serious method-dependency. Nevertheless, the calcinated sewer sludge biochar appears as a sustainable binder option to lime and cement when aiming at improving the shear strength of already excavated sensitive soils.
E. W. Anes; J. I. Loshelder; S. Hov; Priscilla Paniagua; S. Ritter
18th European Conference on Soil Mechanics and Geotechnical Engineering (ECSMGE2024)
E - Environment, water and energy
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