纳米TiO2/纳米MMT/SBR复合改性沥青掺量研究

Analysis on content of nano-TiO2/nano-MMT/SBR composite modified asphalt

针对西部高原地区年平均气温低、紫外线辐射强导致沥青路面极易老化从而产生一系列路面病害的问题,选取纳米TiO2、MMT、SBR三种改性剂制备复合改性沥青。为确定改性剂的适宜掺量,通过响应曲面法结合三大指标试验分析三种改性剂的改性效果,并利用动态剪切流变试验、低温弯曲梁试验对不同纳米TiO2、MMT掺量的改性沥青进行抗老化性能评价从而得到基于沥青抗老化性能的改性剂最佳掺量。结果表明改性剂对三大指标的影响因子排序,即针入度和延度:SBR>纳米TiO2>纳米MMT,软化点:纳米MMT>纳米TiO2>SBR,并通过预测公式确定最佳掺量为4%SBR+1.5%纳米TiO2+4%纳米MMT;通过对改性沥青抗老化评价得到的纳米TiO2、MMT改性剂的最佳掺量与模型结果几乎一致,分别为1%、4%,最佳掺量下的纳米TiO2、MMT可使基质沥青抗老化性能分别提升60%和30%。

Asphalt pavement is easy to be aged with low annual average temperature and strong ultraviolet radiation in western plateau area, so that a series of pavement diseases are produced. Three modifiers nano-TiO2, MMT and SBR are selected to prepare composite modified asphalt. In order to determine the appropriate content of the modifiers, the modified effect of three modifiers is analyzed by response surface methodology with three index tests. The anti-aging performance of modified asphalt with different nano-TiO2 and MMT content is evaluated by dynamic shear rheological test and low temperature bending beam test, and the optimum content of the modifiers based on the anti-aging performance of asphalt is obtained. The influence factors of modifiers on three major indicators are ranked, i.e. penetration and ductility: SBR > nano-TiO2> nano-MMT, softening point: nano-MMT > nano-TiO2> SBR, and the optimum content of modifiers is 4% SBR + 1.5% nano-TiO2 + 4% nano-MMT through prediction formula. The optimum content of nano-TiO2 and MMT is almost the same as that of the model, which are 1% and 4% respectively. Under the optimum content of nano-TiO2 and MMT, the anti-aging performance of the base asphalt can be improved by 60% and 30% respectively.