商合杭高铁CRTSⅢ型板式无砟轨道用自密实混凝土性能研究

A Study of the Performance of the Self-Densifying Concrete for CRTSⅢSlab-Type Ballastless Track of the Shangqiu-Hefei-Hangzhou High-Speed Railway

CRTSⅢ型板式无砟轨道中自密实混凝土性能及施工水平制约着高铁运行过程中的平顺性及后期结构的耐久性。研究立足于商合杭高铁,通过对比普通自密实混凝土(C1)与商合杭高铁施工中两种自密实混凝土(C2、C3)的工作性、力学性能、耐久性,得出相关结论如下:①C1配合比工作性评价劣于C2、C3,尤其是2 h后T500时间、含气量均低于自密实混凝土技术要求,不满足现场施工需求;②3种配合比下力学性能发展趋势为C3>C2>C1;③3种配合比下56 d标准养护条件下电通量、抗盐冻损失量发展趋势为C1>C2>C3。

The performance and construction level of the self-densifying concrete for CRTSⅢslab-type ballastless track restrict the smoothness of high-speed railways during their operation and the durability of the late structures.Based on the Shangqiu-Hefei-Hangzhou High-speed Railway,and through comparing the workability,mechanical properties and durability of ordinary self-densifying concrete(C1)with those of the two types of self compacting concrete(C2、C3)for the Shangqiu-Hefei-Hangzhou High-speed Railway,our research reaches the following relevant conclusions:①The workability of the mix ratio of C1 is found to be inferior to that of C2 and C3,especially after 2 h,the T 500 time and the air content are both lower than those of the technical requirements for self-densifying concrete,namely,not up to the requirements of the site construction;②With the three mix ratios adopted,the developing tendency of their mechanical performance is C3>C2>C1;③Also with the three mix ratios adopted,the developing tendency of the electric flux and the anti-salt freezing loss under the 56 d standard curing conditions is C1>C2>C3.