多聚磷酸与SBS复合改性沥青的改性机制
Modification mechanisms of polyphosphoric acid and SBS on asphalt

为研究多聚磷酸（PPA）与苯乙烯-丁二烯-苯乙烯嵌段共聚物（SBS）复合改性沥青的微观结构和改性机制，对不同掺量（质量分数）的PPA和SBS复合改性沥青样品分别进行了四组分试验、红外光谱试验、荧光显微试验和差示扫描量热试验。结果表明：随着PPA掺量的增加，沥青质含量增多，胶团之间的作用力增强，促使沥青由溶胶结构转变为溶-凝胶结构，提高沥青的黏度；在SBS改性沥青中加入PPA，可增强SBS之间的交联作用及SBS与沥青之间的接枝作用，加强SBS改性沥青的空间网状结构，促使SBS更好地相容于沥青中，改善其高温储存稳定性，并促使SBS分散为细小颗粒，增强溶胀作用，利于SBS发挥改性效果；在低SBS掺量改性沥青中加入PPA，形成的网络结构要优于高SBS掺量单独改性；加入PPA对沥青的玻璃化转变温度没有明显影响，表明PPA对SBS改性沥青的低温性能影响较小。 In order to study the microstructure and modification mechanisms of polyphosphoric acid (PPA) and styrene-butadiene-styrene block copolymer (SBS) on asphalt, fractionation tests, infrared spectrum tests, fluorescence microscopy tests and differential scanning calorimetry tests were conducted on asphalt binders modified with various dosages (by mass) of PPA and SBS. The results show that the asphaltene content and micelle interaction increase with increasing dosage of PPA, and sol structure of binder gradually changes to sol-gel structure, so that the viscosity is improved. The cross-linking, grafting actions and space mesh structure are strengthened with the addition of PPA, and thus the high temperature storage stability is enhanced. The SBS is reduced to smaller particles and the swelling is improved, so that the modification effectiveness of SBS is further exploited. The mesh structure formed in binder modified with PPA and low dosage of SBS is better than that modified with SBS of high dosage. The glass transition temperature is not significantly influenced by the addition of PPA and it indicates that PPA has little effect on the low temperature performance of binders modified with SBS. 国家自然科学基金（51208080）；内蒙古自治区交通运输厅建设科技项目（NJ-2014-21）