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为了提高沥青的高、低温性能,减缓炎热、严寒天气引起的道路病害,延长沥青道路的使用寿命,利用纳米/聚合物复合改性剂,研究能同时提高沥青高、低温性能的复合改性方案。采用硅烷偶联剂KH560对纳米CaCO_3表面进行活化改性,减少纳米材料的团聚现象,并改善有机物与无机物之间的相容性。采用机械搅拌法和高速剪切法制备纳米CaCO_3/SBR复合改性沥青,测定纳米CaCO_3/SBR复合改性沥青的软化点、针入度和延度,同时进行老化试验、动态剪切(dynamic shear rheometer,DSR)试验和小梁弯曲(beam bending rheometer,BBR)试验,研究纳米CaCO_3和SBR对基质沥青物理性能的改善效果,并通过扫描电镜、荧光显微镜及红外光谱微观检测,对纳米CaCO_3/SBR复合改性沥青的微观结构和共混机理进行分析。研究结果表明:纳米CaCO_3和SBR掺量(质量分数,下同)分别为5%和4%时,纳米CaCO_3/SBR复合改性沥青软化点比SK-70#基质沥青提高了22.3℃,针入度降低了1.25mm,延度值大于100cm;老化试验、DSR试验和BBR试验结果也表明纳米CaCO_3/SBR复合改性沥青具有良好的高温性能和低温性能,可满足夏热冬寒地区的要求;加入纳米CaCO_3有效改善了SBR在基质沥青中的分散效果,提高了SBR与沥青界面相的结合能力;纳米CaCO_3/SBR复合改性过程比较复杂,SBR与沥青之间以物理改性为主,纳米材料与沥青之间产生物理改性变化的同时也发生化学反应。
In order to improve the high and low temperature performance of bitumen, alleviate the road diseases caused by hot and cold weather, prolong the service life of asphalt roads and make use of nano / polymer compound modifier to study the compound modification scheme that can improve the high and low temperature properties of bitumen . The silane coupling agent KH560 is used to modify the surface of nano-CaCO 3 to reduce the agglomeration of nano-materials and improve the compatibility between organic and inorganic materials. Nano-CaCO 3 / SBR composite modified bitumen was prepared by mechanical stirring and high-speed shearing. The softening point, penetration and ductility of nano-CaCO 3 / SBR composite modified bitumen were measured and the aging tests, dynamic shear rheometer (DSR) and beam bending rheometer (BBR) were used to study the effect of nano-CaCO 3 and SBR on the physical properties of matrix asphalt. The microstructure of nano-CaCO 3 / SBR was observed by scanning electron microscopy, fluorescence microscopy and infrared spectroscopy. The microstructure and blending mechanism of composite modified asphalt were analyzed. The results show that the softening point of nano-CaCO 3 / SBR composite modified asphalt is 22.3 ℃ higher than that of SK-70 # matrix asphalt when the content of nano-CaCO 3 and SBR (mass fraction, the same below) is 5% and 4% The degree of ductility decreased by 1.25mm and the ductility value was greater than 100cm. The results of aging test, DSR test and BBR test also showed that nano-CaCO_3 / SBR modified bitumen had good high temperature performance and low temperature performance, The addition of nano-CaCO 3 effectively improves the dispersion of SBR in the matrix asphalt and improves the binding ability of the SBR to the bitumen interface phase. The modification process of the nano-CaCO 3 / SBR composite is complex, and the physical modification of the SBR and the bitumen is dominated. A chemical reaction takes place simultaneously with the physical modification of the material and the pitch.