预防双块式道床板混凝土裂缝的施工技术研究

针对高速铁路双块式道床板混凝土开裂现象普遍的缺点，分析了双块式道床板混凝土裂缝的主要形式、形成机理及形成原因，并结合兰新铁路戈壁环境严寒、大温差、强风沙、高温和强日照的实际，研究了具有良好保水性、施工性和抗裂性特点的“三低一高”（低胶材用量、低用水量、低坍落度、高含气量）的道床板混凝土配合比设计技术，轨排框架组装轨排和“适温施工、多点布料、一次完成、二次振捣、五步抹面”的混凝土浇注工艺，以及喷涂高效乳液或水溶液养护剂和覆盖养护棉被的道床板混凝土养护新技术等预防双块式道床板裂缝的施工关键技术。该技术应用效果

Study on Construction Technology Preventing Concrete Cracks on Double-block Slab

In relation to concrete cracking phenomenon commonly found on double-block slab for high speed railway, the main forms as well as the mechanism and causes of the formation thereof were analyzed. Combined with the actual situation of frigid desert environment, large temperature difference, strong sandstorm, high temperature and intensive ultra violet along Lanzhou-Xinjiang Railway, a set of key construction technology was studied, including the proportion design of slab concrete which is of good water retentivity, constructability and crack resistance with low binder content, low water consumption, low slump and high air content; rail assembling by a row of frame frail tooling; concrete placing process: at proper temperature, distributing more, one-time placing, secondary vibrating and five-step finishing; and some maintenance techniques, such as spraying high-performance emulsion or water solution curing agent, and covering curing quilt; all of which could prevent the slab from cracking. Through practice, the technology has been proved to have good effect and may be referred to by similar engineering.