Date of Graduation

12-2018

Document Type

Thesis

Degree Name

Bachelor of Science in Civil Engineering

Degree Level

Undergraduate

Department

Civil Engineering

Advisor

Richard Coffman

Abstract

Abstract

The effects of time and temperature on the moisture content and unit weight profiles, as developed during a centrifuge consolidation process, were observed during the research program that is described herein. Specifically, a Beckman-Coulter Model J6-MI centrifuge with a six-place JS-4.2A swinging bucket rotor was utilized to consolidate kaolinite slurry samples. The consolidation procedure utilized specially designed slurry consolidometers, made from acrylic tubes with inside diameters of 2.63 inches (6.67 cm) and heights of 5.13 inches (13.04 cm). The tested kaolinite slurry samples were created by mixing 400 grams of dry kaolinite clay powder with 200 grams of de-aired deionized water (DI water) to reach an initial water content of 50 percent.

Temperatures of - 10, 0 and 20℃ were utilized within the centrifuge with spin times of 12, 18, 24, and 30 hours. After being removed from the centrifuge, each soil specimen was trimmed into multiple slices of approximately 0.25-inch (0.64 cm) thick. The unit weight and moisture content of each individual slice were calculated and reported. The slurry samples were spun at a fixed centrifugal force of 500 revolutions per minute (RPM) that corresponded to an effective stress at the bottom of the samples of 35.57 kPa at the temperature of -10℃, 50.30 kPa at the temperature of 0℃, and 52.47 kPa at the temperature 20℃. The average unit weight values of the spun samples at 30 hours was 15.52 kN/m3 at the temperature of -10℃, 17.91 kN/m3 at the temperature of 0℃, and 18.25 kN/m3 at the temperature of 20℃. Additionally, the average moisture content values of the spun samples at 30 hours samples were 41.90 percent, 31.22 percent, and 30.22 percent for the testing temperatures of - 10, 0 and 20, respectively.

Keywords

Evaluation, Centrifuge Consolidation, Kaolinite, unit weight

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