The effect of F type polyfiber material to some geotechnical properties of Ankara clay

Being parallel to the development of technology, many soil improvement methods have evolved and different materials have found applications in them. In this thesis, a series of laboratory tests are carried out to investigate the effect of polyfiber material which has found many areas on some geotechnical properties of Ankara clay. Ankara clay, typically brown and highly plastic, as a soil sample and polyfiber (FU-19 and FU-9) as an additive are used in these tests. Initially, some geotechnical properties of Ankara clay are determined and later FU-19 and FU-9 are added to the soil specimens by weight of 0.1, 0.2, 0.3, and 0.4 percent and mixed, thus preparing amended Ankara clay. Proctor and CBR tests conducted on all amended Ankara clay specimens resulted in no change of optimum moisture content and maximum dry density and percentage of CBR value. However triaxial test results show that both type of polyfiber mixtures decreases the cohesion intercept but increases internal friction angle of amended clay specimen considerably. According to data obtained from triaxial compression test, FU-9 increases the shear strength of clay at different confining pressures (1, 2, 3 kg/cm2) in general but FU-19, except 3 kg/cm2 confining pressure , decreases the shear strength of clay at 1 and 2 kg/cm2 confining pressures. Stress-strain relationships of amended clay specimens display that polyfiber increase creep strength of the specimens. In addition, addition of fiber vii to Ankara clay reduces the settlement but does not affect swelling potential of Ankara clay. Key Words : Polyfiber, Clay, Geotechnical Properties, Laboratory Exp.