English abstract
Sabkha soil distributes in many areas, especially along Al Batinah coastal plain in the Sultanate of Oman, this type of the soil is hypersaline and heterogonous properties, which cause a problematic issue for the geotechnical and structural engineers such as large settlement and vary low bearing capacity.
The main objective of this research is to enhance Omani Sabkha soil using soil mixing method both shallow mixing method and deep soil mixing and to replace the cement by Cement kiln dust. The Sabkha soil used in this study is silty sand, according to AASHTO (M145) standard from Al-Auzayba, Sultanate of Oman. For the Shallow mixing the two types of cement OPC & SRC added in the percentage of 2.5,5,7.5, and 10 % (by dry weight of the soil) with or without replacing cement of 50% by CKD. Whereas, the wet deep mixing method is performing using the two types of cement binder with or without replacing cement of 50% by CKD under the condition of binder dosage = 400 kg /m3, water to cement ratio = 0.8, 1, 1.3, and 1.5, and Auger type = 40 ? angle. Both method cured for 7,14 and 28-days.
The study results show that the soil mixing method can be one of the favored methods in enhancing the unconfined compressive strength (UCS) result of Omani sabkha soil to be used in many different construction applications. Using a shallow mixing method of 7.5 % (50% OPC + 50% CKD) by dry weight of the soil can stabilizer sabkha soil to be used as a sub-base layer. Moreover, using the deep wet soil mixing of (50%CKD +50% SRC) binder with 400Kg/m3 dosage at W/C =1 can be used as sub-base. Moreover, using 100% SRC binder with 400Kg/m3 dosage at W/C =0.8 can be used as a base course. This result represents that deep soil mixing method can attain any requirement strength, and it can be used fully in stabilizing sabkha soil to be used in different construction projects.
In addition, replacing 50% of cement by CKD which consider as waste material can attain suitable UCS result as mention above, this reduction in pure cement can save cost and also, reduce the environmental impact.
