硅藻土与蒙脱土协同改善SBS改性沥青性能的研究

为探明硅藻土与蒙脱土协同使用对SBS改性沥青性能的影响，本文通过熔融共混法制备了不同配比的硅藻土/蒙脱土/SBS改性沥青。采用常规物理性能测试、动态剪切流变实验、压力老化和紫外老化实验对硅藻土/蒙脱土/SBS改性沥青的物理、流变和老化性能进行了评价，并利用傅里叶变换红外光谱(FTIR)分析了老化过程中改性沥青化学结构的变化。研究表明，硅藻土与蒙脱土协同使用，不仅提高了SBS改性沥青的软化点与黏度，改善了SBS改性沥青的高温抗变形能力，而且有效降低了蒙脱土对SBS改性沥青低温抗裂性能的不利影响，并能够明显减小压力老化和紫外老化对SBS改性沥青软化点和黏度的负面影响，大幅度提高其延度保留率。蒙脱土掺量为1.5%时，硅藻土的适宜掺量为6%。FTIR分析表明，硅藻土与蒙脱土协同使用抑制了SBS改性沥青压力老化和紫外老化后羰基指数的增加与丁二烯指数的降低，增强了SBS改性沥青的抗老化能力。

Study on improving properties of SBS modified bitumen by diatomite and montmorillonite

For clarifying the influence of diatomite (DA) compounded montmorillonite (MMT) on the properties of SBS modified bitumen (SMB), DA/MMT/SBS modified bitumen with different proportions were prepared by melt blending. The physical, rheological, and aging properties of modified bitumen were evaluated by conventional physical property test, dynamic shear rheological test (DSR), pressure aging and ultraviolet aging test, and the chemical structure changes in modified bitumen before and after aging were analyzed by FTIR. Results showed that the synergistic effect of DA and MMT increased the softening point and viscosity of SMB, enhanced its high-temperature deformation resistance, and reduced the adverse effect of MMT on the low-temperature crack resistance of SMB. Besides, the synergistic effect of DA and MMT reduced the negative effects of pressure aging and ultraviolet aging on the softening point and viscosity of SMB, and the retention rate of ductility was greatly improved. When the content of MMT was 1.5%, the optimum dosage of DA was 6%. FTIR analysis showed that DA compounded MMT could inhibit the increase in carbonyl index and the decrease in butadiene index after pressure aging and ultraviolet aging, which effectively improved the aging resistance of SMB.