Improvement of geotechnical properties of CL soil by kaolinite nanoparticles

In this study, the effect of nanokaolinite particles on geotechnical properties of clayey soils is investigated. The mechanical method of Planetary Ball Mill was used for production of nanoparticles. For this, initial kaolinite powders was milled in Planetary Ball Mill for 10 hours with speed of 500 Rpm of machine. Output powder was in nanometer scale that images produced from FESEM verified this. Then, nanoparticles were mixed with clayey soil (CL) in different weight ratio of dry soil and change percentage of geotechnical properties of treated soils was investigated by compaction, direct shear and cassagrande tests and optimum percentage of added nanokaolinite was determined. Results showed that LL and PL of soil increased while percentage of added nanoparticles increased but since increasing of PL is larger than LL, thus PI is decreased that it is favour for geotechnical engineering for construction. Also with attention to results of compaction tests, density of clayey soil was increased with adding of nanoparticles to an optimum quantity and after it decreased. It is determined from direct shear tests that cohesion of clayey soils increased with adding of nanoparticles to optimum quantity and after it is changeless approximately. Results of XRD and XRF tests showed that chemical integition of nanoparticles produced from planetary ball mill is similar to initial powder and not change.