聚氨酯预聚物改性沥青的制备及其流变行为

为了赋予基质沥青良好的物化性能,增强其在不同环境条件下的适应性,采用聚氨酯预聚物对基质沥青进行改性.基于选择的原材料,首先采用正交试验和直观分析法确定了聚氨酯预聚物改性沥青的最佳制备工艺参数,在此基础上,通过分析聚氨酯预聚物掺量对改性沥青3大指标、韧性、存储稳定性和粘度指标的影响,确定了聚氨酯预聚物改性剂的最佳掺量.其次,借助动态剪切流变试验(DSR)和弯曲梁流变试验(BBR),对比分析了聚氨酯预聚物改性沥青、SBS改性沥青、SBR改性沥青和基质沥青的流变行为.试验结果表明,聚氨酯预聚物改性沥青的最佳制备工艺参数为单位制备量400g、剪切速率4000r/min、剪切温度150℃和剪切时间40min;综合考虑改性沥青3大指标、韧性、存储稳定性、粘度指标和经济性,推荐聚氨酯预聚物改性剂最佳掺量为6%;较其它3种沥青,聚氨酯预聚物改性沥青在52~82℃温度区间内具有最优的高温性能,但其对温度的敏感性最强.同时,聚氨酯预聚物改性沥青在交变应力作用下的弹性性能略低于弹性性能最优的SBS改性沥青.此外,聚氨酯预聚物改性沥青的低温流变性能略低于低温性能最优的SBR改性沥青.

Preparation and rheological behavior of polyurethane pre-polymer modified asphalt

In order to endow good physic-chemical properties to the matrix asphalt and enhance its adaptability under different environmental conditions,the matrix asphalt was modified with polyurethane pre-polymer.The optimal preparation parameters were firstly determined by orthogonal test and visual analysis based on the selected raw materials.On the basis,the optimum dosage of polyurethane pre-polymer modifier was determined by analyzing the influence of polyurethane pre-polymer content on the three major indexes,toughness,storage stability and viscosity index of modified asphalt.Secondly,the rheological behavior of polyurethane pre-polymer modifier asphalt,SBS modified asphalt,SBR modified asphalt and matrix asphalt was compared and analyzed by dynamic shear rheological test (DSR) and bending beam rheological test (BBR).The experimental results show that the optimum preparation parameters of polyurethane pre-polymer modified asphalt are unit preparation amount 400 g,shear rate 4 000 r/min,shear temperature 150℃ and shear time 40 min.Also,considering the three major indicators of modified asphalt,toughness,storage stability,viscosity index and economy,it is recommended that the optimum dosage of polyurethane pre-polymer modifier was 6%.Moreover,compared with other three kinds of asphalt,polyurethane pre-polymer modified asphalt had the best high temperature performance in the temperature range of 52-82℃,but it was of high temperature sensitivity.At the same time,the elastic property of polyurethane pre-polymer modified asphalt under alternating stress was slightly lower than that of SBS modified asphalt with the best elastic property.In addition,the low temperature rheological properties of polyurethane pre-polymer modified asphalt was slightly lower than that of SBR modified asphalt with the best low temperature performance.