Stabilization of saline silty sand using lime and micro silica

Abstract

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.

Keywords

lime stabilization / saline soil / micro silica / bearing capacity / compressive strength / flexible pavements

References

[1] AkiliW., TorranceJ. K.. The development and geotechnical problems of sabkha, with preliminary experiments on the static penetration resistance of cemented sands [J]. Journal of Engineering Geology, 1981, 14: 59-73

[2] Al-AmoudiO. S. B., AbduljawadS. N.. Compressibility and collapse potential of an arid, saline sabkha soil [J]. Engineering Geology, 1995, 39: 185-202

[3] FONCEA C, ACEVEDO P, OLGUIN R. Geotechnical characterization of saline soils [C]// 16th International Conference on Soil Mechanics and Geotechnical Engineering. Osaka, Japan, 2005: 503–506.

[4] KODIKARA J K, RANJITH P G. Modelling of salt migration in stabilized pavement materials [C]// 16th International Conference on Soil Mechanics and Geotechnical Engineering. Osaka, Japan, 2005: 1731–1734.

[5] AibanS. A., Al-AhmadiH. M.. Effect of geotextile and cement on the performance of sabkha subgrade [J]. Building and Environment, 2006, 41: 807-820

[6] Al-AmoudiO. S. B.. A review of the geotechnical and construction problems in sabkha environments and methods of treatment [J]. Arabian Journal of Science and Engineering, 1995, 20: 405-432

[7] Al-RawasA. A., HagoA. W., Al-SarmiH.. Effect of lime, cement and saroj on the swelling potential of an expansive soil from Oman [J]. Building and Environment, 2005, 40: 681-687

[8] YongR. N., OuhadiV. R.. Experimental study on instability of bases on natural and lime/cement-stabilized clayey soils [J]. Applied Clay Science, 2007, 35: 238-249

[9] QinY. H., LiuF. H., ZhouQ.. Influencing factors of compressive strength of solidified inshore saline soil using SH lime-ash [J]. Journal of Central South of Technology, 2008, 15(1): 386-390

[10] SWRI-Soil and Water Research Institute Iran. Soil resources and use potentiality map of Iran [Z] (1:1 000,000), 2000.

[11] KEHL M. Saline soils of IRAN with examples from the alluvial plain of Korbal, Zagros Mountains [C]// International Conference on Soil and Desert. Japan, 2006, 1731–1734.

[12] BUCEA L, SIRIVIVATNANON V. Salinity Hazard and deterioration mechanisms in the built environment [R]. Clayton South, CSIRO, 2003.

[13] GibbsH. J., BaraJ. P.. Stability problems of collapsing soil [J]. Journal of Geotechnical Engineering, ASCE, 1967, 93(4): 577-594

[14] McKENNON H, HAINS J T, NORMAN L, HOFFMAN D. Methods for stabilizing clay-bearing soils by addition of silica and lime, Patent Cooperation Treaty (PCT), Patent Classification: C09K 17/00, Publication Number: Wo 94/06884 [P]. 1994.

[15] KhoshgoftarmaneshA. H., ShariatmadariH., KarimianN., KalbasiM., van der ZeeS. E. A. T. M.. Cadmium and zinc in saline soil solutions and their Concentrations in wheat [J]. J Environ Qual, 2006, 36(4): 1132-1136