老化SBS改性沥青再生与机理分析
Regeneration of aged SBS modified asphalt and its mechanism analysis

为了探究老化SBS改性沥青的有效再生措施，设计2种方案对3种不同老化程度的SBS改性沥青进行再生，方案1为添加再生剂或基质沥青，方案2为添加再生剂+SBS类改性沥青。采用针入度、延度及反映SBS与基质沥青交联作用强弱的韧性SBC指标评价其再生效果，并通过微观相态结构、红外光谱及凝胶渗透色谱分析，探究老化沥青再生的微观机理。研究结果表明：添加再生剂或基质沥青后，老化沥青中沥青质和C=O基团含量减少，胶质和轻质组分含量增大，沥青的针入度和延度增大，但SBS与基质沥青间的交联作用无法恢复，韧性SBC改善效果不明显，甚至因为再生剂和基质沥青的软化作用，导致轻度老化沥青的韧性SBC降低；对于老化较严重的SBS改性沥青，在添加再生剂的基础上，添加SBS类改性沥青后，沥青质和C=O基团含量进一步减少，胶质含量增大，而轻质组分含量略有减少，使得针入度降低，而延度增大，SBS与基质沥青间的交联作用也因为SBS改性剂的补充而恢复，韧性SBC大幅度提高。与SBS改性沥青相比，添加高黏度沥青后，再生沥青的针入度较小，延度和韧性SBC较大，因此，在进行轻度老化SBS改性沥青再生时，不宜添加过多的再生剂或基质沥青，否则会使沥青软化，SBS与基质沥青间的交联作用减弱，韧性降低；对于老化较严重的SBS改性沥青，宜采用添加再生剂+SBS类改性沥青的方法进行再生，使其针入度、延度和韧性尽量接近原样SBS改性沥青的水平。
In order to explore the effective regeneration measures of aged SBS modified asphalt, two methods were designed to regenerate three types of aged SBS modified asphalt with different aging degree. The first method was to add regenerant or base asphalt, while the second method was to add regenerant and modified asphalt of SBS type. Penetration, ductility and toughness were adopted to evaluate the regeneration effect. Toughness reflects the crosslinking strength between SBS and base asphalt, namely SBC index. Then microscopic phase structure, infrared spectrum and gel permeation chromatography of asphalt were analyzed to explore the microscopic mechanism of aged asphalt regeneration. The results show that when adding regenerant or base asphalt to aged SBS modified asphalt, the contents of asphaltene and C=O groups decrease, while the contents of gum and light weight fractions increase. Thus the penetration and ductility of aged SBS modified asphalt increase. But the crosslinking strength between SBS and base asphalt can not be recovered, and there is no obvious improvement of toughness. The toughness of slightly aged SBS asphalt even decreases because of the softening effect of regenerant and base asphalt. For severely aged SBS modified asphalt, on the basis of adding regenerant, adding modified asphalt of SBS type, the content of asphaltene and C=O groups decreases further, while the content of gum increases and the content of light weight fractions decreases slightly. Thus the penetration decreases and the ductility increases. The crosslinking strength between SBS and base asphalt also recovers because of the supplement of SBS, and the toughness improves significantly. Compared with adding SBS modified asphalt, when adding high viscosity asphalt, the penetration of regeneration asphalt is smaller, while the ductility and toughness are higher. Therefore，it is not advisable to regenerate slightly aged SBS asphalt by adding too much regenerant or base