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1、第29卷第1期土木工程與管理學(xué)報(bào)VoI.29No.12012年3月JournalofCivilEngineeringandManagementMar.2012礦物摻合料對自密實(shí)混凝土抗氯離子滲透性的影響張長清,吳海兵,杜明月a,劉齊霞,鄭力種,何廣利,徐文勝,(華中科技大學(xué)a.土木工程與力學(xué)學(xué)院;b.控制結(jié)構(gòu)湖北省重點(diǎn)實(shí)驗(yàn)室,湖北武漢430074)摘要:耐久性是自密實(shí)混凝土(SCC)的重要性質(zhì)。本文應(yīng)用電通量法研究了摻粉煤灰、礦渣的SCC抗氯離子滲透性能,通過對單摻和復(fù)摻時(shí)SCC電通大小的分析發(fā)現(xiàn):粉煤灰和
2、礦渣都能改善SCC的抗氯離子滲透性能,礦渣提高SCC的抗氯離子滲透性能要優(yōu)于粉煤灰,二者復(fù)摻對SCC抗氯離子滲透的復(fù)合疊加效應(yīng)并不明顯。其機(jī)理是粉煤灰和礦渣提高水泥石密實(shí)性,強(qiáng)化混凝土界面過渡區(qū),粉煤灰、礦渣物理化學(xué)吸附作用能固結(jié)cl一,降低cl一滲透性。SCC中摻入摻合料能減少離析、避免泌水,達(dá)到自密實(shí)效果,粉煤灰對混凝土流動(dòng)增大的作用效果要優(yōu)于磨細(xì)礦渣的效果。摻合料復(fù)摻對自密實(shí)混凝土強(qiáng)度具有復(fù)合疊加效應(yīng),混凝土28d強(qiáng)度等級可提高1~2級。關(guān)鍵詞:自密實(shí)混凝土;抗氯離子滲透;粉煤灰;礦渣中圖分類號:TU
3、528.1:TU502.5文獻(xiàn)標(biāo)識(shí)碼:A文章編號:2095-0985(2012)01—0015-05InfluenceofMineralAdmixturesontheResistancetoPenetrationofChlorideIoninSelf-compactingConcreteZHANGChang—qing,Hai—bing,DUMing—yue,LIUQi—xia,ZHENGLi—chong,HEGuang—li.XUWen—sheng,(a.SchoolofCivilEngineeringan
4、dMechanics;b.HubeiKeyLaboratoryofControlStructure,HuazhongUniversityofScienceandTechnology,Wuhan430074,China)Abstract:Durabilityisanimportantpropertyforself—compactingconcrete(SCC).ThispaperstudiedtheresistancetochlorideionpenetrationperformanceofSCCwithad
5、ditionofflyashandslagbasedonconcretecoulombelectricfluxtest.BothflyashandslagcanimprovetheresistancetochlorideionpermeabilityinSCCandslagshowsbettereffeetthanflyash.TheadditionofbothflyashandslagshowlittleqffeetontheresistancetochlorideionpermeabilityinSCC
6、.Themechanismisthattheadditionofflyashorslagcanimprovethedensityofcementpasteandreinforcetheinterfaeialtransitionzonebetweencementpasteandaggregate.BothphysicalandchemicaladsorptionofC1一onthemineraladmixturescontributest0theconsolidationofCl—andthereductio
7、nofCl—permeability.ThemineraladmixturescandecreasetheriskofsegregationandbleedinginSCC.FlyashismoreeffectivethantheslagpowderforimprovingSCCfluidity.TheadditionofbothslagandflyashshowsanenhancedeffectontheSCCstrengthgainandSCCstrengthgradeat28dcanbeincreas
8、edfrom5MPato10MPa.Keywords:self-compactingconcrete;resistancetochlorideionpermeability;flyash;slagpowderMehta認(rèn)為導(dǎo)致混凝土劣化的主要原因之首混凝土基體產(chǎn)生順筋膨脹開裂,加速混凝土結(jié)構(gòu)是鋼筋銹蝕?。氯鹽是一種極強(qiáng)的電解質(zhì),Cl一劣化。滲入混凝土中的cl一以三種形式存在,即滲入混凝土內(nèi)部,能與鋼筋發(fā)生電化學(xué)反