Abstract:
Biochar is a carbonaceous material produced by heating any organic biomass in oxygen-free environment through pyrolysis process. Biochar has several properties that make it an environmentally friendly material. For instance, given its aromatic nature, biochar is highly recalcitrant, so it has great potential to sequester carbon and reduce greenhouse gas emissions. In addition, due to its highly porous nature with high specific surface area can be effectively used for the removal of contaminants from soil and ground water. Since most of the research on biochar applications are about their use as soil amendment, it is important to assess its effect on soil properties from geotechnical point of view. To date, little work has been done in this field. In this study, the effect of biochar addition at varied amounts (3% and 5%) on the liquefaction resistance of loose saturated sand is investigated through simple shear tests. The results show that the addition of biochar increases the liquefaction resistance of sand by delaying the generation of excess pore water pressure and restraining shear strain development. In addition, the results for sand with 5% biochar are compared with those for sand with 5% fines content (silt), and the difference between them is considerable; implying that the mechanism by which biochar increases liquefaction resistance is different from just adding fines to the sand. To provide an insight to the improvement mechanism, the interaction between biochar and water is studied by rheology tests and ESEM analysis. The results presented in this paper provide evidences that this material has potential as an alternative to mitigate soil liquefaction and subsequently mitigate carbon emission and promote plant growth.