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ID:39322717
大小:1.71 MB
页数:6页
时间:2019-06-30
《轻骨料预湿程度对溷合骨料溷凝土抗冻性能影响》由会员上传分享,免费在线阅读,更多相关内容在学术论文-天天文库。
1、第39卷第1期田键等:硅酸三钙电子背散射衍射数据库的建立与标定·35·硅酸盐学报第39卷第1期Vol.39,No.12011年1月JOURNALOFTHECHINESECERAMICSOCIETYJanuary,2011轻骨料预湿程度对混合骨料混凝土抗冻性能影响112孔丽娟,高礼雄,葛勇(1.石家庄铁道大学材料科学与工程学院,石家庄050043;2.哈尔滨工业大学交通学院,哈尔滨150090)摘要:研究了轻骨料预湿程度对不同水胶比混合骨料混凝土28d和90d抗冻性能以及界面区微观结构的影响。结果表明:风干轻骨料自身的多孔结构在混凝土内部起到了“引气”的作用,同时其强烈的吸水作用使
2、得界面层厚度约为预湿轻骨料的2倍,结构也较致密,故其配制的混凝土抗冻性最优。随着轻骨料预湿程度的增加,骨料引气及吸水作用均减弱,故混凝土抗冻性逐渐降低,但预湿轻骨料后期较强的返水作用可使其附近水泥石中的有害孔含量减少,显微硬度提高,界面结构得到持续改善,特别是当水胶比较低时对提高混凝土长期抗冻性能有利。当水胶比较高时,由于水泥石结构比较疏松,此时轻骨料在冻压下导致内部较高的含水率对混凝土抗冻性的不利影响更为突出。即使饱和预湿的轻骨料配制的低水胶比混合骨料混凝土,其抗冻性仍优于同条件下的普通混凝土。关键词:轻骨料;预湿;抗冻性;界面区;显微硬度中图分类号:TU528.2文献标志码:
3、A文章编号:0454–5648(2011)01–0035–06EffectofLightweightAggregatePre-WettingonFrost-ResistanceofCombinedAggregateConcrete112KONGLijuan,GAOLixiong,GEYong(1.SchoolofMaterialsScienceandEngineering,ShijiazhuangTiedaoUniversity,Shijiazhuang050043;2.SchoolofTransportationScienceandEngineering,HarbinInsti
4、tuteofTechnology,Harbin150090,China)Abstract:Thefrost-resistanceofcombinedaggregateconcretepreparedwithdifferentpre-wettingdegreesoflightweightaggregate(LWA)andwater-binderratiosat28dand90dwasinvestigated.ThemicrostructureofLWAandtheinterfacialzonewereexamined,andtheeffectofLWApre-wettingonfr
5、ost-resistanceofconcretewasanalyzed.Theresultsshowthattheporousair-dryLWAcanplaytheroleof“air-entraining”,andthestrongwaterabsorbingeffectcanmakethethicknessofinterfacialzoneofabouttwotimesofthatofprewettedLWA,aswellasthedensificationoftheinterfacialpaste.Thefrost-resistanceofconcreteprepared
6、withair-dryLWAwassuperior.Theair-entrainingandwater-absorbingeffectofLWAbothdecreasedwiththeincreaseofLWApre-wettingdegree,thusleadingtothegradualdecreaseofconcretefrost-resistance.However,thestrongwater-releasingeffectofpre-wettedLWAinlateragecouldimprovetheinterfacialstructurethatdecreasedt
7、hevolumecontentofharmfulporesandincreasedthemicro-hardnessoftheinterfacialpaste,whichcouldfavorthelongtermfrost-resistanceofconcrete,especiallyforconcretewithalowerwaterbinderratio.Forconcretewithahigherwater-binderratio,thehighwatercontentof
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