二氧化钛改性石墨烯对碱激发矿渣复合材料力学性能及微观结构的影响

Effect of Titanium Dioxide Modified Graphene on Mechanical Properties and Microstructure of Alkali-activated Slag Composites

为改善石墨烯的疏水性,利用二氧化钛的插层法制备分散性良好的二氧化钛改性石墨烯(TiO2-RGO),并将其掺入碱激发矿渣基体中制备石墨烯质量分数分别为0,0.01%,0.02%和0.03%的石墨烯增强碱激发复合材料,研究其力学性能和微观结构以及石墨烯的增强增韧机理。结果表明:在石墨烯掺量为0.03%范围内时,碱激发水泥复合材料的弯曲、抗压强度随石墨烯的质量分数的增加而增大。同时,当添加0.03%石墨烯时,碱激发复合材料的弯曲韧性较空白试样提高了80%以上。通过扫描电子显微镜、X射线衍射仪对复合材料的微观结构进行表征,发现可延展的石墨烯可填充孔隙、增加与基体的接触面积,并通过裂纹偏转和分支以及石墨烯的拉出和锚固作用,有效地提高碱激发复合材料的弯曲韧性、改善脆性破坏特性,但不会改变基体的物相特征。

Titanium dioxide modified graphene(TiO2-RGO) with a good dispersibility was prepared by an intercalation method, and it was incorporated into alkali-activated slag to prepare graphene-enhanced alkali-activated composites with different graphene mass fractions(i.e., 0, 0.01%, 0.02% and 0.03%). The mechanical properties and microstructure and the graphene enhancement were investigated. The results show that the bending and compressive strengths of the alkali-activated cement composites increase with the increase of the mass fraction of graphene. The bending toughness of the alkali-activated composite material with 0.03% graphene is increased by more than 80%, compared to the normal sample. The microstructure of graphene was characterized by scanning electron microscopy and X-ray diffraction. It is indicated that ductile graphene can fill the pores, increase the contact area with the matrix, and effectively improve the crack deflection and branching as well as the pull-out and anchoring of graphene. The alkali-activated composite has poor bending toughness and brittleness, but does not change the phase composition of the matrix.