高速铁路CRTSⅢ型板式无砟轨道自密实混凝土性能研究

摘要

In order to settle the problems about high construction ability,high comfort and high durability of high-speed railway CRTS Ⅲ slab-type ballastless track,self-compacting concrete( SCC ) was used as ballastless track filling layer material which has high flowing ability,high plastic stability and low shrinkage. According to the closed space structure and bearing ability of filling layer,three types of SCC with different compressive strength grade ( C30,C40 and C50) were made by combining with SCC requirements of designing ballastless track structure, volume stability test,chloride ion penetration test and unilateral freeze-thaw test were implemented,and workability, volume stability and durability were studied. The results showed that three kinds of SCC have a good workability which is suitable to filling layer construction of slab ballastless track,plastic-shrinkage of SCC increases with compressive strength grade increasing,drying-shrinkage of three types show different changing laws with the same water-binder ratio and the same unilateral water content and have good durability,chloride ion impermeability of SCC decreases with increasing of the compressive strength grade,and freeze-deicing salt resistance of SCC increases with compressive strength grade increasing.%为解决高速铁路CRTSⅢ型板式无砟轨道结构高施工性、高平顺性和高耐久性要求，采用具有高流动性、高塑性稳定性和低收缩变形的自密实混凝土作为无砟轨道充填层材料。针对充填层的封闭结构空间和承载功能，并结合设计和无砟轨道结构对自密实混凝土的要求，制备了 C30，C40和 C50三种强度等级自密实混凝土，进行体积稳定性试验、氯离子渗透试验和单边冻融试验，研究其工作性能、体积稳定性和耐久性能。结果表明：三种自密实混凝土均具有适合板式无砟轨道充填层施工的良好工作性能；其塑性收缩变形均随着强度等级的提高而增大；在水胶比相同和单方用水量相同两种情况下三种自密实混凝土的干燥收缩变形呈现出完全相反的变化规律；三种自密实混凝土均具有良好耐久性，抗氯离子渗透能力随强度等级的提高而降低，抗盐冻性能则随着强度等级的提高而增强。