Investigation of the effect of calcium in minerals used in stabilization of clay by geopolymer method

In this study, geopolymer with limpet mineral was used to stabilize the clay. Also, an attempt has been made to investigate the role of chemical properties of calcium oxide (CaO) in this mineral for soil stabilization through geopolymer method. In this regard, a combination of sodium hydroxide and silicate adhesive has been used as a base activator. Uniaxial compressive strength test was used as the main criterion for comparing stabilized geopolymer samples. Besides, direct shear test was used to investigate the adhesion and internal friction angle of stabilized samples. Chemical analysis of reactions and elemental lineage changes were performed by electron imaging (SEM) on a geopolymer sample. The results show that increasing minerals rises uniaxial compressive strength (UCS). The results of microstructural analysis show the reaction of limpet mineral with soil and the formation of aluminosilicate gel in geopolymer samples. Based on the results obtained in this study in order to completely eliminate the use of cement and lime in soil stabilization process, the use of minerals with high CaO element in their structure were examined. These materials can significantly increase the strength of soil stabilized by geopolymer method. Utilizing 10 percent of mineral in geopolymer method caused UCS of 671 KPa and 2.04 MPa in 7 and 45 curing time, respectively.