考虑胶浆黏附性的泡沫沥青冷再生混合料性能

Performance of Cold Recycled Mixture with Foamed Asphalt Considering Adhesion of Mastics

采用正交设计方法,研究了粉胶比、沥青老化程度及老化沥青黏附试验温度3个因素对泡沫沥青胶浆与老化沥青间黏附特性的影响.利用自研测试设备,获取了泡沫沥青胶浆与老化沥青间的黏附强度,通过极差分析及方差分析,得到3个因素的影响程度及每个因素下的最优水平;结合泡沫沥青冷再生混合料(CRMFA)干/湿劈裂强度试验,确定了泡沫沥青冷再生混合料的最佳粉胶比.在此基础上,设计了3种拌和工艺.采用冻融劈裂(ITS)试验、车辙试验及无侧限抗压强度试验,分析了拌和工艺对泡沫沥青冷再生混合料路用性能的影响.结果表明:粉胶比对泡沫沥青胶浆的黏附特性影响最大,老化沥青黏附试验温度次之,沥青老化程度的影响最小;泡沫沥青胶浆与老化沥青黏附强度最优水平为粉胶比2∶1+沥青老化程度(85min RTFOT+10h PAV)+老化沥青黏附试验温度50℃;泡沫沥青冷再生混合料的最佳粉胶比为2∶1;拌和工艺对泡沫沥青冷再生混合料路用性能具有显著影响,将粗集料及沥青路面铣刨回收的旧料(RAP)与1/2的泡沫沥青拌和,依次加入细集料、矿粉及水泥,再喷入剩余1/2的泡沫沥青,拌和制备得到的混合料路用性能最优.

The influence of filler-asphalt ratio,aging degree and temperature of aged asphalt on the bonding strength between the foamed asphalt mastics and aged asphalts was investigated based on orthogonal design method.The bonding strengths between the mastics and aged asphalts were obtained using a self-developed testing equipment.The impact of the three factors and the optimal level of each factor were determined using methods of range analysis and variance analysis.The optimal filler-asphalt ratio was obtained with a combination of the dry/wet indirect tensile strength(ITS)test of cold recycled mixture with foamed asphalt(CRMFA).Then,three kinds of mixing processes of CRMFA were proposed,and the performances of the samples produced by different mixing processes were investigated based on freeze-thaw tensile strength,wheel tracking and unconfined compressive strength tests.The results show that the adhesion of foamed asphalt mastics is most affected by filler-asphalt ratio,followed by temperature of aged asphalt,while the aging degree exhibits the minimal effect.The optimal levels of the three factors affecting the bond strength between the mastics and aging asphalts are 2∶1 of filler-asphalt ratio+(85min RTFOT+10h PAV)aging degree of asphalt+50℃of aged asphalt temperature,respectively.The optimal filler-asphalt ratio 2∶1 is determined based on the dry/wet ITS test.Comparing with the performances of samples produced by the three different mixing processes,it is found that the mixing process displays a significant influence on the performances of mixtures.The mixing process that blending coarse aggregates together with RAP firstly,then adding fine aggregate,mineral powder and cement in turn,at last adding remaining asphalt for last mixing is the best process.