为提高再生沥青的再生效果和经济效益,使再生沥青在不增加再生剂掺量以及保证不损失低温性能的情况下能有效提高高温性能,将RA-F0110型再生剂和OP-900型再生剂分别以8:2的比例与新沥青混合分别制成A型再生剂和B型再生剂;采用马尔文激光粒度分析仪对纳米SiO2材料进行粒径测试;依据SUPERPAVE规范对70#基质沥青先进行85 min薄膜烘箱短期老化,再进行20 h压力老化,制成旧沥青;采用硅烷偶联剂KH-550对未改性的纳米SiO2材料进行有机化表面改性;采用扫描电镜观测有机化改性前后纳米SiO2尺寸的变化;采用高速剪切仪对有机化改性后的纳米SiO2、再生剂和旧沥青进行剪切制成纳米再生沥青.通过针入度、延度、软化点和PG分级试验,以优先恢复低温性能为标准,确定了再生剂种类的选取和合理掺量,通过PG分级中的动态剪切流变试验和低温弯曲梁流变试验,以PG连续分级中的高低温温度服务范围为标准,确定了纳米材料的掺量.试验表明:选用A型再生剂的再生沥青的再生效果优于选用B型再生剂的再生沥青.在相同再生剂掺量的情况下,添加了纳米材料的再生沥青表现出更好的高温稳定性和低温抗裂性能.当纳米材料的掺量为5%, A型再生剂掺量为20%时,纳米再生沥青胶结料的各项指标均能达到最佳状态.
In order to improve the regenerative effect,economic benefits and high temperature performance of recycling asphalt without increase the amount of recycling agent and to ensure that no loss of low temperature performance, the mixture with 20% new asphalt and 80% RA - F0110 recycling agent is prepared as recycling agent A,and the mixture with 20% new asphalt and 80% OP-900 recycling agent is prepared as the recycling agent B. The size of nano-SiO2is measured by Malvern Mastersizer. According to SUPERPAVE specification,the No.70 base asphalt is aged by 85 min RTFO and 20 h PAV. The nano-SiO2 surface is modified by silane coupling agent KH-550,the sizes of nano-SiO2 before and after modification are observed by SEM. Using high speed shear apparatus, the aged mixture with modified nano-SiO2 and recycling agent are cut to make the nano-recycled asphalt. To restore low temperature performance as priority, by tests of penetration,softening point,ductility and performance grade, the kinds and reasonable additive amounts of recycling agents are determined. Taking (HT-LT) in PG continuous grading as the criterion, by tests of DSR & BBR in PG, additive amount of nanomaterial is determined. The test result shows that (1) the regeneration of the recycling agent A is better than the recycling agent B;(2) with the same recycling agent content, the recycled asphalt added with nano-SiO2,shows better high temperature stability and low temperature anti-cracking performance;(3) when adding amount of nano-SiO2 is 5%,and adding amount of recycling asphalt A is 20%,each performance indicator of nano-recycled asphalt is optimal.