水泥乳化沥青砂浆长期变形性能研究

As we known, the cement asphalt mortar (CA mortar) filling layer is one of important units and plays a key role in the durability of slab track system. However, after 3 or 5 years service, the survey results showed that this filling layer was severely deteriorated due to the accumulative deformation of CA mortar. This appearance indicates that the study is almost blank in CA mortar deterioration. Therefore, further researches are quite necessary and should be urgently performed ...In this project, firstly, the effects of temperature, age and loading rate on the static mechanical performance of CA mortar will be studied respectively. Secondly, the roles of amplitudes and frequency of dynamic loading in the dynamics performance of mortar will also be disclosed respectively. According to the experimental results, firstly, the combining influences of internal factors of CA mortar, such as the composition, micro-structure and viscous-elastic character etc., on the degradation mechanism of mortar due to deformation will be analyzed. Secondly, the static and dynamic response of ballastless track structure, that caused by the accumulative deformation of CA mortar layer, will be calculated. As a result, the limit value of accumulative deformation will be presented, and technical ways to improve the resistance of CA mortar against irreversible deformation will also be proposed...Therefore, this project sounds very important to improve a better understanding on the viscous-elastic character and deformation of CA mortar, resulting in providing experimental and theoretical experiences to perfect the durability design of ballastless track structure and to enrich technical ways to reasonably repair CA mortar.

水泥乳化沥青砂浆(CA砂浆)充填层是板式轨道的重要结构部件。现场调查发现，部分砂浆充填层服役3-5年后出现了因其累积变形过大导致的严重劣化现象，表明人们对CA砂浆长期变形性能以及由此引起的充填层破坏过程缺乏科学认识，有待深入研究。.本项目通过试验，分别对温度、龄期、加载速率对CA砂浆的静力性能以及振幅、频率对交变荷载作用下CA砂浆的动力性能的影响开展深入研究。重点探讨材料组分、微观结构和粘弹特性等因素对CA砂浆长期变形性能的影响规律；揭示其相互关系和作用机理；计算分析CA砂浆充填层累积变形对无砟轨道结构静动力响应的影响，提出砂浆充填层累积变形的限值和降低CA砂浆不可逆变形的技术途径。.研究成果将深化对CA砂浆粘弹特性特别是其长期变形性能的认识，为完善板式无砟轨道设计理论及养护维修技术提供相应支撑。

水泥乳化沥青砂浆（CA砂浆）是高速铁路板式无砟轨道结构中的关键工程材料，其长期变形和粘弹力学性能等对板式轨道结构的稳定性、安全性和耐久性有重要影响。本项目针对典型服役条件，系统研究了CA砂浆的变形性能及其微细观响应机制，探明了主要材料组分对其变形性能的作用机理。.考虑列车瞬时荷载的加载速率效应，研究获得了CRTSI、CRTSII型CA砂浆在静、动荷载作用下的应力-应变关系；建立了CA砂浆在不同应变率条件下的统计损伤本构模型。. 考虑荷载作用的长期性，研究发现了CA砂浆徐变变形的速率渐减与相对稳定的两阶段变形模式，且I型CA砂浆的徐变度大于II型CA砂浆；基于不可逆热力学原理建立的徐变模型预测得到I、II型CA砂浆在100年服役周期内的变形分别约为0.31mm和0.0835mm。.针对CA砂浆的组成特点，系统研究了应变水平、温度对CA砂浆应力松弛性能的影响规律，得到CA砂浆的两阶段应力松弛过程，即速率渐减应力松弛阶段和速率相对稳定应力松弛阶段。建立了CA砂浆的应力松弛模型。. 考虑服役环境的温度变化，研究发现CA砂浆在恒定荷载作用下变形的温度依赖性和在恒定变形条件下应力的温度敏感性均具有两个转变温度、三阶段的变化特征，沥灰比和水灰比的增大均会增大变形和应力的变化速率。基于粘弹性理论，建立了CA砂浆的静态热力学模型。.在交变荷载和温度的耦合作用下，研究表明了CA砂浆具有明显的应变滞后效应，且随着沥青含量的增大，CA砂浆的应变滞后效应越明显。CA砂浆的储存模量、损耗模量、损耗因子具有显著的温度、频率依赖性；建立的本构模型能够有效预测CA砂浆的动态热力学性能。.CA砂浆的粘弹特性对其长期变形的影响机理有待进一步深入研究。. 研究成果可为板式无砟轨道的结构设计提供理论指导，并有助于板式无砟轨道的运营安全性评估和CA砂浆的服役全寿命预测。