Micromechanical Mechanism Of Interaction Between Clay Minerals And Colloidal Oxides

Red clay was widely used as an important industrial raw material in the environmental,material,and chemical industries.Based on the components of Guiyang red clay,while focusing on edge effects and surface chemistry,and based on illite particles,this paper used molecular simulation methods to synthesize Reax FF and Clay FF force fields to study the periodic illite/colloidal oxide-water structure and the large-scale model of mixed colloidal oxide or water based on hexagonal illite particles,aiming to explore the intensity formation and degradation of red clay at the atomic scale.Based on the theory of molecular dynamics,this paper first based on the periodic illite/colloidal oxide-water structure,preliminarily explored the cementation ability and water deterioration mechanism of different colloidal oxides and clay minerals,and concluded that the microstructure of the iron-rich mixture was first destroyed in the metal oxide intercalation,while the aluminum-rich mixture was destroyed in the illite crystal plate,so the existence of Al-O bonds was conducive to the mechanical properties of the hybrid system and could improve the anisotropy of the clay system.In periodic clay mineral-aqueous systems,an increase in moisture content led to a decrease in tensile strength and Young’s modulus.On this basis,to further explore the influence of water/colloidal oxide on the mechanical properties of the clay system,the physicochemical properties and mechanical properties of the mixed system were obtained by mixing the water/colloidal oxide with the aggregate model of illite particles in line with the SEM image.In the aggregate model of illite particles,the increase of moisture content decreased the proportion of edge-hypotenuse configuration,increased the proportion of surface overlapping configuration,the pore width increased with the increase of moisture content,water molecules were mainly distributed within 1 nm on the surface of clay minerals,and the enthalpy of hydration release decreased with the increase of moisture content.With the increase of moisture content,the tensile strength and Young’s modulus of illite/water large-scale model were generally positively correlated with moisture content when the moisture content was lower than 40%,but the tensile strength and Young’s modulus of 50% moisture content were lower than 40%.Both the stress value of the stress-strain curve,as well as Young’s modulus and tensile strength were about30-100 times lower than the infinite periodic model,and the numerical units of this model were closer to macroscopic experiments.In the colloidal oxide/illite structure,the oxide first agglomerated,and then gradually attached to the surface of illite particles,so that there was no longer a contact point between different illite particles,and the attachment of colloidal oxide assumed the role of "envelope" and "bridge".The mechanical properties of the colloidal oxide/illite hybrid structure were no longer affected by the distribution of illite particles in all directions but were consistent with the trend of lattice volume and inversely correlated with porosity.Overall,this study provided realistic predictions for a deeper understanding of the mechanical properties of clay mineral/aqueous systems and mixed colloidal oxides or water,which could provide fundamental insights into macrostructures.