天興洲大橋鐵路引橋及相關(guān)配套工程大體積混凝土施工作業(yè)指導(dǎo)書(shū).doc

大體積混凝土施工作業(yè)指導(dǎo)書(shū)
1. 總則
1.1 適用范圍
武漢天興洲大橋鐵路引橋及其相關(guān)工程配套部分TZQ-1標(biāo)段內(nèi)樁基承臺(tái)及墩臺(tái)大體積混凝土施工
1.2 大體積混凝土的定義
在《普通混凝土配合比設(shè)計(jì)規(guī)程》（JGJ/T55）中對(duì)大體積混凝土解釋為“混凝土結(jié)構(gòu)物中實(shí)體最小尺寸大于或等于1m或易引起裂縫的混凝土”。
1.3大體積混凝土裂縫產(chǎn)生原因的機(jī)理分析
   混凝土中產(chǎn)生裂縫有多種原因，主要是溫度和濕度的變化，混凝土的脆性和不均勻性，以及結(jié)構(gòu)不合理，原材料不合格（如堿骨料反應(yīng)），模板變形，基礎(chǔ)不均勻沉降等。
    　混凝土硬化期間水泥放出大量水化熱，內(nèi)部溫度不斷上升，在表面引起拉應(yīng)力。后期在降溫過(guò)程中，由于受到基礎(chǔ)或老混凝上的約束，又會(huì)在混凝土內(nèi)部出現(xiàn)拉應(yīng)力。氣溫的
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
 

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