废机油底渣对沥青的不利影响及机理初探

发布时间：2018-03-18 03:34

本文选题：道路工程　切入点：废机油底渣(WEOB)　出处：《建筑材料学报》2017年04期 　论文类型：期刊论文

【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.
[Abstract]:In order to accurately estimate the effect of waste oil bottom slag on the long-term durability of asphalt, modified asphalt was prepared by adding waste oil bottom slag with different dosage in straight-run asphalt. At the same time, the aging of modified asphalt was carried out to varying degrees: rotative film oven aging (RTFOO), pressure chamber aging (PAV) and expanded pressure chamber aging (ExPAV). The critical crack opening displacement (CTODD) of two-sided notched tensile test was used to study the ductile fracture properties of asphalt. The influence of physical hardening on the low temperature reliability of asphalt was evaluated by using the graded loss obtained from the Ex-BBRs test of extended bending beam, and the long term durability of asphalt was evaluated by 螖 Tc index (the difference between the critical temperature of creep stiffness and the critical temperature of creep rate). In addition, atomic force microscopy (AFM) was used to observe the microstructure and morphology of asphalt before and after adding WEOB. The results showed that the adverse effect of WEOB on the low temperature performance of asphalt could be recognized more obviously by prolonging the aging time. However, the aging time of conventional asphalt (WEOB) can not obviously capture this adverse effect. Adding WEOB can lead to physical hardening of asphalt and decrease of ductile fracture resistance. WEOB can obviously increase the grain size of wax in asphalt. The low temperature crystallization of wax grain and the stress concentration caused by the phase boundary are the main reasons for the long-term low temperature performance of the waste oil bottom slag.
【作者单位】：西南交通大学土木工程学院;西南交通大学道路工程四川省重点实验室;加拿大女王大学化学学院;西华大学土木建筑与环境学院;四川高速公路建设开发总公司;
【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)
【分类号】：U414

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