Influence of bagasse ash, calcium carbide residue and polyester fiber addition on shear strength of organic clay

Abstract

Organic clay has bad engineering properties. It is compressible, sensitive to the changes of water content; and it has poor bearing capacity and shear strength. Therefore, the research regarding improvement of this soil is intensively performed and continually in progress. In this research, bagasse ash (BA), calcium carbide residue (CCR) and polyester fiber were used to improve the shear strength of organic clay. A set of laboratory experiment were performed to study the effects of BA, CCR and polyester fiber inclusions on the shear strength of organic clay. To obtain optimum moisture content (OMC), standard compaction test was worked out for original soil. The oven dried BA (varied as 10 %wt, 20 %wt and 30 %wt) were mixed with the soil, and water was added to its OMC. Then, 1 to 2 %wt freely oriented polyester fiber was mixed with BA-soil samples. The BA-soil specimen and BA-soil specimen containing polyester fiber was investigated through direct shear tests. Finally, 4 %wt CCR was added to both BA-soil mixtures, and BA-soil mixture with fiber inclusion. The direct shear tests were then carried out on those samples with 14, 28 and 36 days curing period. This research shows that calcium carbide residue increases shear strength of BA-soil samples and BA-soil specimens with fiber inclusion. It shows also that fiber inclusion increases ductility of treated soil. However, the use of BA only does not significantly increase the shear strength of stabilized soil.