天兴洲大桥铁路引桥及相关配套工程大体积混凝土施工作业指导书.doc

大体积混凝土施工作业指导书
1. 总则
1.1 适用范围
武汉天兴洲大桥铁路引桥及其相关工程配套部分TZQ-1标段内桩基承台及墩台大体积混凝土施工
1.2 大体积混凝土的定义
在《普通混凝土配合比设计规程》（JGJ/T55）中对大体积混凝土解释为“混凝土结构物中实体最小尺寸大于或等于1m或易引起裂缝的混凝土”。
1.3大体积混凝土裂缝产生原因的机理分析
   混凝土中产生裂缝有多种原因，主要是温度和湿度的变化，混凝土的脆性和不均匀性，以及结构不合理，原材料不合格（如碱骨料反应），模板变形，基础不均匀沉降等。
    　混凝土硬化期间水泥放出大量水化热，内部温度不断上升，在表面引起拉应力。后期在降温过程中，由于受到基础或老混凝上的约束，又会在混凝土内部出现拉应力。气温的
Mass Concrete Construction Work Instructions
1. General
1.1 Scope
Tianxingzhou Bridge Railway Approach and related engineering support within some TZQ-1 Lot of pile caps and substructure of massive concrete
1.2 The definition of mass concrete
In the "ordinary concrete mix design procedures" (JGJ/T55) on mass concrete as "solid concrete structure in the minimum size of greater than or equal to 1m, or apt to cause cracks in the concrete."
1.3 The causes of concrete cracks in the mechanism of
   Concrete cracks for many reasons, mainly temperature and humidity changes, brittle and uneven concrete, as well as unreasonable structure, failure of raw materials (such as alkali-aggregate reaction), template deformation, differential settlement of foundation.
    During the release of a large number of hardened concrete cement hydration heat, the internal temperature rise, causing the surface tension stress. Late in the cooling process, due to coagulation on the basis of the constraints or old, what will occur in the internal tensile stress of concrete. Temperature