Filter design for a dispersive soil stabilized by various additives

This thesis presents a series of empirical studies to define dispersibility of a base soil and its stabilization to prevent dispersibility to be able to be used as a filter. A low plastic clay (CL) with intermediate dispersibility was used as a base soil during the experimental studies. An environmentally-friendly biopolymer xanthan gum (XG) and bentonite were separately added to the base soil with the ratios of 0.5, 1, 2, 3 % by dry weight. These specimens were tested at the end of 0, 7, 14, 28 days in the pinhole, crumb and double hydrometer tests. Furthermore, narli sand (NS) and crushed sand stone (CSS) were also used in the permeability tests in order to understand the effect of different particle shape on the filter design. XG and tire waste powder (TWP) at the contents of 0%, 1%, 3% by dry weight were separately added to the NS and CSS samples in order to decrease the permeability values. The specimens were tested at the end of 0, 7, 28, 56 day curing time using the constant head permeability test. Eventually, CL type base soil with intermediate dispersibility was stabilized by using the XG. It was also found that XG and TWP additives decreased the permeability values of the sand samples substantially. XG was found to be strongly effective on the results of both testing series