Treatment of Marine Clay with Hydrated Lime and Quicklime

Abstract

The objective of this research is to improve dredged marine sediments with lime for potential use in earthfill works. Dredging work is usually necessary for coastal construction work and this material should be removed in an economical way. Marine clay samples used in the study were dredged in Gemlik Bay near Bursa, in Turkey. Geotechnical tests were conducted to determine the properties of the natural clay samples, including classification tests, unconfined compression (UC) and California bearing ratio (CBR) tests. The optimum lime content by weight was determined as 5 % using the Eades and Grim pH method, Atterberg limits and unconfined compression strength tests. Standard and modified Proctor tests were conducted to determine optimum water content and maximum dry density of the soil. Maximum dry density values decreased, optimum water content values increased, and Proctor curves becomes flatter with the addition of lime. Because the natural water content of the clay is around 40 % and the optimum water content of the samples with lime is around 16 %, not only hydrated lime but also quicklime is used for the improvement and drying of the marine clay soil. The original unconfined compressive strength and CBR value of the dredging soil were close to zero because of high water content. One month after improvement by lime, the unconfined compressive strength value reached 550 kPa and soaked CBR value was 35 without swelling. Unconfined compressive tests and CBR test results demonstrate that this type of marine clay can be improved with lime and can be economically utilized as a fill material in earthfill works.