多聚磷酸改性沥青流变性能

为研究多聚磷酸(PPA)对沥青性能的影响规律与作用机理, 采用四组分分析试验和沥青三大指标试验研究了PPA对不同基质沥青化学组分的影响, 基于动态剪切流变仪(DSR)开展了沥青温度扫描试验与频率扫描试验, 分析了不同配比的PPA改性沥青、PPA/SBS改性沥青与PPA/橡胶粉改性沥青在不同温度、不同动态频率加载条件下的流变性能变化趋势。分析结果表明: 随着PPA含量(质量分数, 后同)的增加, 沥青质含量逐渐提高, 油分(饱和分与芳香分)含量减小, 沥青逐渐由溶胶结构转变成溶-凝胶结构, 沥青高温性能逐渐增强; PPA改性沥青的高温性能与基质沥青的沥青质含量相关, 沥青质含量大的基质沥青经PPA改性后其沥青质含量提升最大, 针入度降低最多, 具备更好的高温性能; 基质沥青、SBS改性沥青与橡胶粉改性沥青掺入PPA后, 其抗车辙因子分别提高了1.0~8.2、0.8~13.9与2.9~19.7 kPa, 表明PPA可有效改善基质沥青、SBS改性沥青和橡胶粉改性沥青的高温、感温及流变性能, 增强沥青的弹性特征, 提高其抵抗剪切变形能力; 与单一改性沥青相比, PPA复合改性沥青的流变性能改善效果更为明显, PPA与聚合物改性沥青之间存在良好的相容性; 随着PPA含量的增加, 沥青10℃延度逐渐降低, 当PPA含量为1.5%时, 基质沥青、SBS改性沥青与橡胶粉改性沥青10℃延度分别下降77%、64%与39%, 表明PPA对沥青的低温性能存在一定负面作用, 建议PPA含量不宜超过1.0%;PPA/SBS改性沥青最佳复配比为1.0%PPA复配3%SBS, PPA/橡胶粉改性沥青最佳复配比为0.75%PPA复配15%橡胶粉。 

Rheological property of polyphosphoric acid modified asphalt

To study the effect and action mechanism of polyphosphoric acid(PPA) on the asphalt performance, the effects of PPA on the chemical compositions of different matrix asphalts were studied by performing the four-component analysis test and three major indices test of asphalt. Based on the dynamic shear rheometer(DSR), the temperature scanning test and frequency scanning test of asphalt were carried out. The changing trends of rheological properties of PPA modified asphalt, PPA/SBS modified asphalt and PPA/rubber powder modified asphalt with different ratios under different temperatures and different dynamic frequency loading conditions were analyzed. Analysis result shows that as the PPA content(mass fraction, same later) increases, the asphaltene content increases gradually, and the oil content(saturation and aromatic) decreases. The asphalt changes gradually from the sol structure to the solution-gel structure, and the high temperature performance of asphalt enhances gradually. The high temperature performance of PPA modified asphalt is related to the asphaltene content of matrix asphalt. After being modified by PPA, the asphaltene content of matrix asphalt with high asphaltene content increases the most, its penetration reduces the most, and it has better high temperature performance. The rutting resistance factors of matrix asphalt, SBS modified asphalt and rubber powder modified asphalt increase by 1.0-8.2, 0.8-13.9 and 2.9-19.7 kPa, respectively, indicating that the PPA can effectively improve the high temperature performances, temperature sensitivities, and rheological properties of matrix asphalt, SBS modified asphalt and rubber powder modified asphalt, enhance the elastic characteristics of the asphalts, and improve their resistances to shear deformation. Compared with the single modified asphalt, the rheological property of PPA composite modified asphalt improves more obviously. There exists a good compatibility between the PPA and the polymer modified asphalt. As the PPA content increases, the ductility of asphalt at 10 ℃ decreases gradually. When the PPA content is 1.5%, the ductilities of matrix asphalt, SBS modified asphalt and rubber powder modified asphalt at 10 ℃ decrease by 77%, 64% and 39%, respectively, indicating that the PPA has a certain negative effect on the low temperature performance of asphalt. It is recommended that the PPA content should not exceed 1.0%. The optimal compound ratio of PPA/SBS modified asphalt is 1.0% PPA compounding 3%. The optimal compound ratio of PPA/rubber powder modified asphalt is 0.75% PPA compounding 15% rubber powder.