Field Investigation of Highway Subgrade Silty Soil Treated with Lignin
Lignin is a by-product of paper or timber industry, and it has not been fully utilized all over the world. Improper disposal of lignin would pose significant risk to public health and surrounding environment. A field test was conducted to investigate the road performance of problem silty soil treated with lignin in highway subgrade applications. Quicklime, a traditional soil stabilizer, was selected as a control binder for comparison purpose. A series of field tests, including California Bearing Ratio (CBR) test, resilient modulus (Ep) test, and Benkelman beam deflection test were performed to explore the evolution of mechanical properties of lignin treated silty soil during the curing period. The effects of additive content and curing time on the bearing capacity of the treated soil were also investigated. The field test results reveal that lignin possesses a good ability to improve the bearing capacity of the silty soil. 12% lignin treated soil exhibits higher values of CBR, Ep, and lower value of resilient deflection as compared with those of 8% quicklime treated soil. The use of lignin as a stabilization chemical mixture for silty soil may be one of the viable answers to the reuse of organic by-product in geotechnical engineering.
KeywordsSilty soil Recycled materials Stabilization Strength
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