兰新二线高性能混凝土桥墩抗裂性试验研究

Study Anti-cracking Performance of High-performance Concrete Bridge Pier Used in the Second Railway of Lanxin

针对该线新疆段大风、大温差、严重干旱缺水的自然环境特点,进行了室内与现场的抗裂性试验研究。分析了墩体裂缝产生的原因,得出在新疆恶劣的自然环境下保温、保湿养护能显著提高混凝土墩体早期抗裂性的结论。保温、保湿养护,能减少混凝土内部水分向外散失,减小混凝土发生干缩与塑性收缩的机率;同时保证水化热散失均匀,减小混凝土墩内外温差,降低由于温度应力产生的裂缝。结果表明:采用合理的养护方式可使此类环境下高性能混凝土桥墩抗裂性得到明显提高。

Due to the bad environment around,the high-performance concrete bridge pier which used in the second railway of Lan-xin（in Xinjiang province） is very difficult to adopt traditional curing method.According to the bad natural environment,the indoor and on-site cracking-resistance experimental research had done.Analyzed the causes and mechanisms of the crack.We draw a conclusion that the curing methods have obvious influence on piers early-cracking in bad natural environment especially in xinjiang province.By using heat and moisture curing material,reduce water loss,cut the risk of dry shrinkage and plastic shrinkage during the maintenance period.Secondly,using the thermal insulation materials,ensure the hydration heat dissipating evenly.Reduce the temperature difference between inside and outside of concrete.Finally,reduce the temperature stress.Experiment results shows that adopting rational curing methods can make the high performance concrete bridge pier anti-cracking performance improved obviously in Xinjiang province.