天然沥青改性沥青热性质与微观结构研究

Thermal Property and Micro Structure Analysis on Asphalt Modified with Natural Asphalt

为了明确沥青微观组成结构与宏观路用性能的联系,以不同掺量天然沥青改性沥青为研究对象,利用差热分析、热重、质谱分析表征沥青结合料的热分解过程,研究沥青结合料的热性质和微观组成结构变化过程。结果表明:在适宜的天然沥青掺量范围内,差示扫描量热曲线的吸热峰能量随掺量增大而逐渐减小;沥青试样在230℃左右出现明显的质量损失,与沥青闪点温度一致;沥青残留质量比与针入度、软化点和抗车辙因子等高温指标具有较好的相关性;离子流强度在400℃左右出现显著变化,表现为较强烈的分解反应,热分解主要产物有CO,H2O,CH4和CO2,表明沥青中存在丰富的COOH,—CO—,—CHO—,COOCH3等结构。

To clarify the relation between asphalt microstructure and macroscopic road performance,asphalt modified with natural asphalt of different contents as research object,the pyrolysis process of asphalt binders was characterized with differential scanning calorimetry（DSC）,thermal gravimetric（TG）and mass spectrum（MS）.The thermal properties and microstructure changing process were analyzed.The results show that endothermic peak energy decreases with the increase of natural asphalt dosage in DSC curve under the appropriate range of natural asphalt dosage.With TG curve of five asphalt samples,there is noticeable mass loss at about 230 ℃.The flash point is corresponding to the mass loss temperature.There is a good correlation between the residual mass ratio and high temperature performance indicator,such as penetration,softening point and rutting factor.In MS curve,significant change in ionic strength occurs at about 400 ℃,manifesting a strong pyrolysis reaction.The main products of asphalt decomposition reaction around this temperature are CO,H2 O,CH4and CO2,which indicatesthat there are COOH,—CO—,—CHO— and COOCH3 in asphalt binder.