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对预应力钢筋进行灌浆为确保预应力混凝土结构物的耐久性具有很重要的作用。在日平均温度4℃以下时期,必须进行灌浆冬施时,如无适当的养护措施,灌浆遭受冻结就不可能达到所要求的强度,灌浆受冻膨胀,沿套管的混凝土就会产生裂缝,这是应该竭力避免的。冬施灌浆的养护方法有喷射热气法和灌浆内电热线复合养护法等,但对于大跨长度的灌浆,以及大桥桁梁断面内无空间且与大气接触面较大的冬施现场,要保持必要的养护温度则较困难。为此通过实验和工程实践开发出一种用于预应力混凝土与跨连续复合桁桥冬施灌浆养护新方法即载热体养护法。
Grouting of prestressed reinforcement plays an important role in ensuring the durability of prestressed concrete structures. During the period when the average daily temperature is below 4 ℃, winter grouting must be carried out. If there is no proper curing measures, the grout will not be able to achieve the required strength when it is frozen. The grouting will be frozen and expanded, cracks will be generated in the concrete along the casing, This should be avoided. The winter grouting conservation methods are jetting hot gas and grouting electric heating compound curing method, but for the long-span grouting, as well as the bridge girder cross-section without space and large contact surface with the atmosphere winter facilities to be maintained The necessary curing temperature is more difficult. To this end, through experiment and engineering practice, a new method for curing winter-applied grouting of prestressed concrete and cross-continuous composite girder has been developed.