双块式无砟轨道道床板混凝土裂缝控制技术

Crack Control Technologies for Slab Concrete of Double-block Ballastless Track

针对高速铁路双块式无砟轨道道床板现浇混凝土易开裂问题,通过室内试验研究了道床板混凝土裂缝控制技术,同时基于多场耦合模型对道床板混凝土开裂风险进行了定量评估。结果表明:掺入抗裂剂对道床板混凝土工作性能和后期强度影响较小,早期明显体积膨胀,有效补偿了混凝土收缩;掺入抗裂剂后道床板中心和上表面开裂风险系数由1.0以上降低至0.7以下,基本不开裂。经工程现场应用,掺入抗裂剂的道床板混凝土浇筑完成6个月后未发生开裂,混凝土抗裂性能较好。

Aiming at the problem that the slab cast-in-situ concrete of double-block ballastless track of high speed railway is easy to crack,the crack control technologies for slab concrete was studied through indoor test,and the crack risk of slab concrete was quantitatively evaluated based on multi-field coupling model. The results show that the addition of anti-cracking agent has little effect on the working performance and later strength of slab concrete,and there is obvious volume expansion in the early stage,which effectively compensates the shrinkage of concrete. After adding anticracking agent,the cracking risk coefficient of the center and upper surface of the slab is reduced from more than 1.0 to less than 0.7,and there is basically no cracking. Through the field application of the project,the slab concrete mixed with anti-cracking agent has not cracked after 6 months,and the concrete has good anti-cracking performance.