Recently, the demand for environmentally friendly products has been increasing worldwide. In this study, the improvement of cohesive soil with a biopolymer material (Guar Gum), which is a type of additive and organic, environmentally friendly, is investigated. For this purpose, various laboratory tests have been conducted on the biopolymer-added soils, including the compaction test, the Atterberg limits test, and the unconfined compressive strength test. The samples for tests have been prepared that the biopolymer has been mixed with the soil in three different proportions to determine the optimum mixing ratio. Also, in the biopolymer-added soils, some samples have been cured at varying times to determine the effect of curing periods on their strength. For comparison, the tests performed on improved soils have been also carried out on the untreated cohesive soil. For a comprehensive evaluation, scanning electron microscopy analyses (SEM analyses) was carried out on some samples. On the other hand, X-ray fluorescence analysis (XRF analysis) was performed to have an idea about the composition of the cohesive soil. Consequently, the biopolymer additive material has improved the geotechnical properties of the cohesive soil in all mixing ratios and curing times. Moreover, the optimum mixing ratio has been obtained at 1% according to the results of tests.

Keywords: Weak soil improvement by biopolymer, Environmentally friendly additive, SEM analyses of soils, Curing effect, Organic additive,

Submitted on January 23, 2001.
Final Acceptance on May 05, 2021.
Discussion open until August 31, 2021.
DOI: 10.28927/SR.2021.060020