高速铁路现浇道床混凝土防裂措施对比研究

Comparative research on crack-prevention measures for cast-in-place track bed concrete of high speed railway

研究了优化配合比参数设计以及掺入内养护材料、化学减缩剂和玻璃纤维等功能材料对高速铁路现浇道床板抗裂性能的影响。室内试验结果表明:“低胶凝材料用量、低用水量、低坍落度和高含气量”的制备技术路线可显著降低混凝土的早期塑性收缩及干燥收缩,同时大幅降低平板抗裂试件的24h总开裂面积;化学减缩剂和内养护材料均可显著降低混凝土的塑性收缩,而玻璃纤维未表现出显著减缩效果。实体浇筑试验段表明:“三低一高”+内养护材料的综合技术实际抗裂效果最佳。

In this paper, the effects of optimizing mix parameter design and aciding functional materials such as internal curing c*mhaetmeriicaalsl shrinkage reducing agent,glass fiber on the cast-in-place track bed concrete were mainly studied. The laboratory experimental results show that the technological route of "low cementitious material dosage. low water consumption,low slump and high air content" can significantly reduce the early plastic shrinkage and drying shrinkage of concrete, and at the same time can greatly reduce the total 24 h cracking area of slab crack specimens;chemical shrinkage reducing agent and internal curing materials both can significantly decrease the plastic shrinkage of concrete, while glass fiber did not show obviously reduction effect. The results of solid pouring test show that the comprehensive technology of "three low and one high"+ internal curing materials had the best practical crack resistance effect.