Effect of Stabilization with Black Liquor and Lignosulfonates on Shear Strength Parameters of Clayey Soil

نوع: Type: Thesis

مقطع: Segment: masters

عنوان: Title: Effect of Stabilization with Black Liquor and Lignosulfonates on Shear Strength Parameters of Clayey Soil

ارائه دهنده: Provider: Vahid Tahzibi

اساتید راهنما: Supervisors: Masoud Makarchian (Ph.D)

اساتید مشاور: Advisory Professors:

اساتید ممتحن یا داور: Examining professors or referees:

زمان و تاریخ ارائه: Time and date of presentation: March, 17, 2021

مکان ارائه: Place of presentation:

چکیده: Abstract: Due to the increasing concerns on environmental pollution, the recycling of industrial by-products had become a popular practice worldwide. Many conventional soil admixture (e.g., cement, lime, fly ash, and gypsum) are generally used to improve the mechanical properties of the soils. The applicability of most of these conventional stabilizers of soil is limited to particular soils. In addition, this type of admixture causes many pollution problems by changing the pH of groundwater. Chemical stabilization of problematic soils with lignin-based biomass by-product was being considered as one of the varies answers to this need. Despite limited research about the effect of lignin-based stabilizers on sandy soils and silt, few studies have been conducted on the impact of these substances on clay soils. In this thesis, two alternative stabilizer -Lignosulfonate and Black Liquor is investigated. Several basic properties of kaolinite clay, such as Atterberg limits, proctor compaction, unconfined compressive strength (UCS), stress-strain behavior, modulus of elasticity, and secant modulus of elasticity (E50) are evaluated. The Lignosulfonate and Black Liquor contents were 0.5, 0.75, 1, 2, 3 and 4% by weight of the dry soil and specimens were cured for 1, 7, 14, and 28 days. Moreover, a series of specimens were dried after 28 days of curing and studied in the dry state. Results show that the Lignosulfonate (LS) and black liquor treatment leads to a considerable reduction in plasticity index (PI) of the soil. In addition, stabilization with LS has slightly increased the optimum water content and slightly decreased the maximum dry unit weight of the soil. Lignosulfonate and black liquor both have increased the stiffness and UCS of the soil without leading to a considerable brittle behavior. Black liquor has a better effect on UCS of the soil comparing with Lignosulfonate in optimum moisture state. In dry state, lignosulfonate has a better effect on USC than black liqueur. The increase in strength properties is attributed to the electrostatic reaction that occurs between the mixture of admixture-water and soil particles. Key Words: Soil Improvement, Soil Stabilization, Lignosulfonate, Black Liqour, unconfined compressive strength, UCS

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