Stabilization of saline silty sand using lime and micro silica

Many construction and post-construction problems have been reported in the literature when saline soils have been used without understanding of their abnormal behavior, especially their inferior bearing capacity in the natural condition. The strength of these soils further decreases on soaking. Saline soil deposits cover extensive areas in central Iran and are associated with geotechnical problems such as excessive differential settlement, susceptibility to strength loss and collapse upon wetting. Because of these characteristics, some of the roads constructed on saline soils in Taleghan area have exhibited deterioration in the form of raveling, cracking and landslides. The main objective of this work is to improve the load-bearing capacity of pavements constructed on Taleghan saline soils using lime and micro silica. Soil samples from Hashtgerd-Taleghan road were collected and tested for improving their properties using lime and micro silica at different dosages ranging from 0 to 6%. The load-bearing capacity of stabilized soil mixtures was evaluated using California Bearing Ratio (CBR) and unconfined compressive strength tests. The test results indicate that the lime improves the performance of soil significantly. The addition of 2% lime with 3% micro silica has satisfied the strength-deformation requirements. Therefore, improved soil can be used as a good subbase in flexible pavements.