Laboratory Evaluation of the Geotechnical Properties of Biochar Amended Mississippi Chalk

The upkeep and rehabilitation of infrastructure damage related to the shrinking and swelling of expansive soils have cost the United States billions of dollars. Biochar, an innovative and eco-friendly additive proven to improve soil permeability, nutrient retention, and mechanical properties, is investigated as an additive to Mississippi chalk. The index properties of the chalk were determined and used to characterize its nature. The mechanical properties of the chalk amended with 6% and 12% biochar were evaluated via the Proctor compaction, compression, and direct shear tests, and the observed results were analyzed to make comparative remarks on how the behavior of the chalk evolved with biochar percentage. The chalk's compactibility, compressibility, and shear strength increased as the biochar percentage increased. The cohesion coefficient decreased while the friction angle increased with an increased biochar percentage. The increased shear strength of biochar-amended soil is a promising observation of biochar's potential as a construction material in geo-transportation projects.