L4 Volumn changes of Concrete.ppt

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1、Lesson4VolumeChangesofConcreteBackgroundKnowledge所涉及到的课程：建筑材料、钢筋混凝土基本原理。混凝土的特性：混凝土是重要的人工混合材料，基本力学性能包括混凝土的抗压、抗拉、抗剪强度与混凝土的变形，影响混凝土力学性能的主要因素有重复加载、偏心受压、龄期、收缩与徐变等。本课文涉及到混凝土的收缩、膨胀、混凝土的徐变等。ThecontentofthetextPartparagraphContent1Theintroductionofvolumechang

2、esofconcrete12~12Theshrinkageofconcrete213~14Expansionduetoriseintemperature315~36ThecreepofconcreteThetextcanbedividedinto3parts.NewWordsandExpressionofParagraph1shrinkvi.收缩shrinkageexpandvt.扩张,使膨胀expansionexpansionjoint伸缩缝moisturecontent含水量Concrete

3、undergoesvolumechangesduringhardening.Ifitlosesmoisturebyevaporation,itshrinks,butiftheconcretehardensinwater,itexpands.Thecausesofthevolumechangesinconcretecanbeattributedtochangesinmoisturecontent,chemicalreactionofthecementwithwater,variationintem

4、perature,andappliedloads.Paragraph1(Introductionofconcretevolumechanges)volumen.体积，卷，册，音量，大量，量appliedloads外加荷载NewWordsandExpressionofParagraph2thecapillarytension毛细管张力,微张力cementpaste水泥浆Thechangeinthevolumeofdryingconcreteisnotequaltothevolumeofwaterr

5、emoved.Theevaporationoffreewatercauseslittleornoshrinkage.Asconcretecontinuestodry,waterevaporatesandthevolumeoftherestrainedcementpastechanges,causingconcretetoshrink,probablyduetothecapillarytensionthatdevelopsinthewaterremaininginconcrete.Part2Shr

6、inkage变干燥的混凝土体积变化不等于移除的水的体积。Paragraph2restrainedadj.克制的，受限制的restraineddeformation，restrainedsupportEmptyingofthecapillariescausesalossofwaterwithoutshrinkage.Butoncetheabsorbedwaterisremoved,shrinkageoccurs.Paragraph2capillary[kə'piləri,'kæpi-]n.毛细血管

7、；微血管absorbedwater吸附水；吸收水NewWordsandExpressionofParagraph3~9Paragraph4concretemix混凝土混合物concretemixertruckParagraph5finenessofcement水泥细度Paragraph6gradationofaggregate骨料级配Paragraph8admixturen.混合；添加物；掺和剂Paragraph9reinforcementn.加固；加强reinforcementbar钢筋条re

8、inforcementcage钢筋笼Manyfactorsinfluencetheshrinkageofconcretecausedbythevariationsinmoistureconditions.1.Cementandwatercontent.Themorecementorwatercontentintheconcretemix,thegreatertheshrinkage.2.Compositionandfinenessofcement.High-early-strengthandlo