HCSA膨胀剂制备CRTSⅢ型无砟轨道自密实混凝土

Preparation of Self-compacting Concrete for CRTSⅢ Ballastless Track with HCSA Expansive Agent

硫铝酸钙一氧化钙类双膨胀源膨胀剂HCSA具有膨胀能大、绝湿膨胀、膨胀与强度协调发展优点。针对CRTSⅢ型轨道板密闭环境特性,采用HCSA膨胀剂制备轨道板填充用自密实混凝土,有效解决了自密实混凝土收缩大、体积稳定性差和易开裂难题。新拌自密实混凝土流动性、填充性和抗离析性能良好,坍落扩展度680mm、L型仪充填比0.92、J环障碍高差14mm。硬化混凝土抗压强度、耐久性能优异,56d抗压强度48.9MPa、电通量374C、抗盐冻性170g/m^2、干燥收缩值291×10^(-6)。揭板后,自密实混凝土板面密实、平整,无裂纹,性能满足TJ/GW 112-2013要求。

HCSA calcium sulphoaluminate hydrate-calcium hydroxide double sources expansive agent has the advantage of high restrained expansion rate, anhydrous expansion,coordinated development of expansion and strength. According to the closed environment of CTRS Ⅲ ballastless track, HCSA expansive agent was used to prepare self-compacting concrete(SCC) to solve the problems of great shrinkage, poor volume stability and easy to crack. Fresh SCC has good flowability, filling-ability and anti-segregation. Slump flow, L-box filling ratio and J-ring blocking step of SCC were 680 mm, 0.92 and 14 mm, respectively. Besides, harden concrete also had good mechanical property and durability. Compressive strength, electric flux, salt-freezing resistance and drying shrinkage of SCC at 56 days were48.9 MPa, 374 C, 170 g/m^2 and 291×10^(-6). SCC slab was dense, even, crack-free after uncover the track board. The performance of SCC satisfied the requirements of TJ/GW 112-2013.