严寒地区高速铁路岔区现浇道床混凝土裂缝控制技术

Crack Control Technology of Cast-in-suit Roadbed Concrete of High Speed Railway Switch Area in Severe Cold Area

针对严寒地区高速铁路岔区现浇道床混凝土易开裂、冻胀粉化的问题,从混凝土配合比设计、功能材料使用、施工工艺3方面提出降低道床混凝土开裂及粉化风险的综合抗裂技术措施,并开展了室内混凝土塑性收缩试验和早期抗裂试验。结果表明:采用综合抗裂技术能够有效降低混凝土的早期收缩率,显著提升混凝土的抗裂性能。经在京沈客运专线线下双块式轨枕试验段足尺试验验证,采用综合抗裂技术施工试验段的裂缝数量减少90%,总开裂面积仅为采用常规技术施工试验段的4%。

Aiming at the problems of easy cracking and frost heave powdering of cast-in-situ roadbed concrete of high speed railway switch area in severe cold area,the comprehensive anti-cracking technical measures for reducing the cracking and powdering risk of roadbed concrete were put forward from three aspects of concrete mix proportion design, functional material use and construction technology,and indoor plastic shrinkage test and early anti-cracking test of concrete were carried out. The results show that comprehensive anti-cracking technology can effectively reduce the early shrinkage rate of concrete and significantly improve the anti-cracking performance of concrete. The full-scale test of the two-block sleeper test section under the Beijing-Shenyang passenger dedicated line shows that the number of cracks in the construction test section decreases by 90% by using comprehensive anti-cracking technology,and the total crack area is only 4% of the crack area in the construction test section by using conventional technology.