增黏剂对城市轨道交通板式无砟轨道自密实混凝土性能的影响

Influence of Tackifier on Performance of Self⁃compacting Concrete for Ballastless Track in Urban Rail Transit

研究了增黏剂掺量对新拌自密实混凝土工作性能和硬化自密实混凝土力学性能、耐久性能和体积稳定性的影响。结果表明:增黏剂掺量由6.0%降至3.0%时,自密实混凝土塑性黏度、屈服应力和流动时间显著降低,贯入度、静态离析百分数、56 d抗压强度和干燥收缩率均增大,电通量变化不大;增黏剂掺量3.0%的自密实混凝土不论是新拌的还是硬化后各项性能指标均满足Q/CR 596—2017《高速铁路CRTSⅢ型板式无砟轨道自密实混凝土》要求。通过无砟轨道工艺性试验发现,不论是灌板时还是揭板后自密实混凝土质量均满足规范要求,且每立方米成本比增黏剂掺量6%的高速铁路CRTSⅢ型板式无砟轨道自密实混凝土降低16.8%。因此,增黏剂掺量3.0%的自密实混凝土可用于城市轨道交通板式无砟轨道结构。

This study delves into the influence of tackifier content on the workability,mechanical properties,durability,and volume stability of freshly mixed and cured self-compacting concrete used in urban rail transit ballastless track construction.The findings reveal a noteworthy decline in plastic viscosity,yield stress,and flow time as tackifier content drops from 6.0%to 3.0%.Simultaneously,penetration depth,static segregation percentage,56 d compressive strength,and dry shrinkage all register an increase.Remarkably,electrical conductivity remains relatively stable.Self-compacting concrete featuring a 3.0%tackifier content consistently meets the requirements set forth in Q/CR 596—2017 Specification of Self-compacting Concrete for High-speed Railway CRTSⅢSlab Ballastless Track,both in its freshly mixed and cured states.In construction process tests for slab tracks,it was observed that concrete quality adheres to specifications during casting and demolding.Furthermore,the cost per cubic meter is 16.8%lower compared to high speed rail CRTSⅢslab ballastless track with 6.0%tackifier content.Consequently,self-compacting concrete with 3.0%tackifier content stands as a cost-effective solution for urban rail transit slab track structures.