Resumen de Effect of sodium silicate and cement on the improvement of engineering properties of organic soil

Veronica Gacambi Kiuna, Zülküf Kaya

• The study is aimed at evaluating the effect of adding sodium silicate and cement to organic soil. Geotechnical properties of organic soil are determined before and after the addition of the stabilizing materials, which in this case are cement and sodium silicate. The results obtained after treatment were analyzed and evaluated to determine whether the strength values reached are adequate for strong subgrades for pavement, and airports construction. Organic soil samples used in this study were obtained from Kayseri Free Area in Turkey. Index properties and geotechnical properties of organic soil, which was identified as sample P, were determined and this formed the reference upon which strength improvements of each mix design sample were obtained. Optimum moisture content and maximum dry density of the soil and the various mixes were obtained using standard proctor test. Unconfined compressive tests (UCS), California bearing ratio (CBR), and Falling head permeability tests were used to determine geotechnical properties. UCS tests were conducted on air cured samples for 1, 7, and 28 days. Soaked and unsoaked CBR samples were tested after 1, 7 and 28 days. Hydraulic conductivity was determined using the falling head permeability test. From the experiments, sodium silicate and cement were seen to improve the strength of organic soil and provide acceptable subgrade strength and CBR values. CBR and UCS tests indicated that longer curing periods improved strength even more. Higher values were obtained for 7 days cured samples than for 1-day samples with the highest values being obtained for 28 days cured samples. Design mixes with higher cement and sodium silicate compositions gave the highest values of strength. In conclusion, sodium silicate and cement give positive results when it comes to stabilizing organic soil.