USP改性沥青的降温效果和流变特性研究

Evaluation of Cooling Effect and Rheological Properties of USP Modified Asphalt

USP改性剂作为新型降黏剂多用于沥青混合料性能优化研究,对流变行为的研究还较少。采用动态剪切流变仪(DSR)和弯曲梁流变仪(BBR)重点分析了USP改性沥青降温效果和流变特性。研究发现,随着USP掺量增加,改性沥青的降黏、高温、疲劳和低温性能均呈现出规律性变化。USP改性剂起到了降黏降温效果,沥青混合料试验也验证了降温效果且满足温拌水准。高温性能指标,如软化点、复数模量(G^(*))、相位角(δ)、车辙因子(G^(*)/sinδ)、不可恢复蠕变(J_(nr3.2))和应变恢复率(R)持续损伤,而J_(nr3.2)相较于高温PG分级,能更有效评价高温抗变形能力;耐疲劳性能显著提升。连续分级温度(T_(c))表明,USP改性沥青的低温临界温度持续降低,低温抗开裂性能显著提升。USP改性剂具有较好温拌剂的潜质,为低温寒冷地区拓展了添加材料。

As a new type of viscosity reducing agent,USP modifier is mainly used in the study of the performance evaluation of asphalt mixture,Performance optimization and there are few studies on the rheological behavior of asphalt.Dynamic shear rheometer(DSR)and bending beam rheometer(BBR)are used to analyze the comprehensive properties of USP modified asphalt.Results showed that with the increase of USP dosage,the effect of viscosity reducing,high temperature,fatigue and low temperature properties of modified asphalt shows the regular changes.USP plays an important role in reducing viscosity and cooling temperature effect of asphalt,and the asphalt mixture also proves the effective cooling effect and meets the warm mixing level.High temperature performance(softening point,complex modulus,phase angle,rut factor,irrecoverable creep Jnr and strain recovery rate R)is damaged,J_(nr3.2) can effectively evaluate its high temperature resistance to permanent deformation compared with high temperature performance grade(PG).The fatigue life is enhanced significantly.The continuous grading temperature T_(c) shows that the low-temperature critical temperature of USP warm-mixed modified asphalt is continuously decreasing,and the ability to resist the low-temperature cracking behavior is significantly enhanced.As a result,USP modifier has the potential as a good warm mixer,expanding the addition of materials for low temperature and cold areas.