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时间:2019-05-11
《木质素磺酸钙对水泥水化的影响》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、万方数据第33卷第4期2o5年4月硅酸盐学报JOURNAL0FTHECHINESECERAMICSOCIETYVbl_33。№.4April,2005木质素磺酸钙对水泥水化的影响庞煜霞,邱学青,杨东杰(华南理工大学化工与能源学院,广州510640)摘要:研究了掺加木质素磺酸钙(calciumlignosulfonate,cLs)后水泥净浆体系的水化速度、水化产物生成量,以及硬化水泥石的微观结构及孔隙结构的变化。cLs大幅度延缓了水泥水化放热,降低了水化速度,使3~10h内水泥的水化程度减少,但对1d后的水化程度影响不大且能促进水泥的后期水化。x射线衍射分析表明高掺量cLs
2、促进硬化水泥中生成钙矾石,抑制水化硅酸钙(CsH)的早期生成,但对csH的后期生成无影响。扫描电镜观察发现:cLs的掺加抑制了水化产物晶体的生长,使csH凝胶难以形成空间网架,钙矾石晶体变得纤细。随cLs掺量的增加,硬化水泥中总孔隙容积增加,30nm以上的孔隙显著减少,10nm以下的微孔数量大幅度增加,平均孔径减小。掺加cLs的水泥浆体水化产物晶体发育不完全,硬化水泥的孔隙容积明显增加,是硬化水泥28d龄期内抗压强度显著下降的主要原因。关键词:木质素磺酸钙;水泥水化;水化产物;微观结构;孔隙结构中图分类号:TQl72.46文献标识码:A文章编号:0454—5648(200
3、5)04一0477一07INFLUENCEoFCALCIUMLIGNoSULFoNATEONCEMENTHYDRATIoNPANGYMzta,QIUxueqing,YANGDongjie(SchoolofChemicalandEnergyEngineering,SouthChinaUniversityofTechnology,Guangzhou510640,China)Abstract:Hydrationratesandhydrationproductsofcementpaste,microstructuresandporestructuresofhydratedceme
4、ntblendedwithcalciumlignosulfonate(CLS)werestudied.Theheat—releaseofcementhydrationisdelayedremarkablybyCLSandthehydrationrateisretarded,resultinginreducingthehydrationdegreeduringthe“rst3——lOh.However,CLShaslittleeffectonhydrationdegreeofcementpasteafter1dandcanpromotethe10ng—termhydrati
5、on,X—raydiffractionanalysisshowsthatCLScanpromotethegrowthofettringiteandrestrainthegrowthofCSHatearly。age,whilethe10ng—termgrowthofCSHisnotbeaffected.Accordingtothescanningelectronmicroscopeobservation,thecrystal—growthofhydrationproductsisre—strainedbyCLSwiththeresultthatCSHcannotformgr
6、idstructureandtheettringitecrystalsbecomefiner.Nevertheless,thecompositionofettringiteisnotchanged.ThetotalporevolumeofhydratedcementincreaseswiththeincreasingofCLSdosage,theproportionofporewithadiameterover30nmdecreasesobviouslyandtheproportionofporewithadiameterlessthan1Onmincreasesshar
7、ply.TheaverageporediameterofhydratedcementblendedwithCLSdecreases.Theincompletegrowthofhydratecrystalsandtheremarkableincreaseofporev01umeinhydratedcementcausedbyair—entrainingpropertyofCLSarethemainreasonsthatIeadtothestrengthdecreasingofcementpasteblendedwithCLSwi
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