摘要
为准确预估废机油底渣(WEOB)对沥青长期耐久性的影响,通过在直馏沥青中添加不同用量的废机油底渣来制备改性沥青,并对改性沥青进行不同程度的老化:旋转薄膜烘箱老化(RTFO),压力箱老化(PAV)及扩展压力箱老化(ExPAV).采用双边缺口拉伸(DENT)试验的临界裂纹张开位移(CTOD)研究沥青的抗延性断裂性能,采用扩展弯曲梁流变(Ex-BBR)试验得到的分级损失来评估物理硬化对沥青低温可靠性的影响,采用ΔTc指标(蠕变劲度临界温度与蠕变速率临界温度之差)评估沥青的长期耐久性,此外通过原子力显微镜(AFM)观察添加WEOB前后沥青的微观结构形态.结果表明:延长老化时间(ExPAV)可以更明显识别WEOB对沥青低温性能的不利影响,而常规沥青老化时间(PAV)并不能明显捕捉这种不利影响;添加WEOB会使沥青产生物理硬化并导致抗延性断裂性能降低;WEOB可使沥青中蜡晶粒明显增加,而蜡晶粒的低温结晶及其相界造成的应力集中是导致废机油底渣长期低温性能降低的主要原因.
In order to accurately predict the impact of waste oil bottom residue（WEOB）on the long-term durability of asphalt,WEOB of different contents was added into the straight run asphalt.Different degree aging：rotating thin film oven（RTFO）,pressure aging vessel（PAV）and extend pressure aging vessel（ExPAV）were performed on the asphalt.Double edge notch tensile（DENT）test was used to characterize the ductile fracture performance of asphalt.Performance grade of physically aged asphalt was tested using extended bending beam rheometer（Ex-BBR）method.The difference between creep stiffness critical temperatrue and creep rate critical temperature（ΔTc）was used to evaluate the duration of asphalt.Microstructure morphology of asphalts before and after adding WEOB was observed using atomic force microscope（AFM）.Test results show that extending the aging time can more clearly identify the adverse effect of WEOB on the low temperature properties of asphalt whereas the conventional aging time does not significantly capture this detrimental effect.Anti-ductile fracture performance decreases and physical hardening may occur in asphalt with WEOB.Wax crystal may increase significantly in asphalt with WEOB.Wax crystal and stress concentration caused by the phase boundaries are the main reason leading to decrease of long term low temperature.
出处
《建筑材料学报》
EI
CAS
CSCD
北大核心
2017年第4期646-650,共5页
Journal of Building Materials
基金
绿色建筑与节能四川省重点实验室开放课题项目(szjj2015-074)
国家留学基金委公派留学基金项目(201607000097)
