- 劉素瑞1,楊久俊1,2,3,王戰忠4,張 磊1,2,3,榮 輝1
2015年第6期
摘要
引用本文
摘??要:通過分析混凝土裂縫愈合前后的力學性能、裂縫寬度、物相組成和組織結構,研究了不同濃度Na2CO3溶液(0、2%、4%、6%)環境下混凝土裂縫的自愈合性能。結果表明,Na2CO3溶液對混凝土裂縫的自愈合效果明顯優于水;不同濃度Na2CO3溶液環境下,混凝土的強度、波速均隨齡期延長逐漸增大,且增長速率前期較大,后隨齡期的延長趨于平緩;6%Na2CO3溶液環境下,混凝土強度恢復效果最明顯,49d時完全恢復,60d時強度恢復率增至106.1%;2%Na2CO3溶液環境下,60d時混凝土強度恢復率僅為73.5%;4%Na2CO3溶液環境下,混凝土強度恢復效果處于兩者之間。隨Na2CO3溶液濃度的增大,裂縫中C-S-H凝膠、CaCO3晶體等水化產物增多,體積增大,二者通過填充作用和膠結作用,使裂縫逐漸愈合。Abstract:Concreteself-healingperformancesunderdifferentconcentrationofsodiumcarbonatesolution(0,2%,4%,6%)werestudiedbyanalyzingmechanicalproperty,crackwidth,phasecompositionandmicrostructurebeforeandaftertherepairmentofconcretecrack.Theexperimentalresultsindicatedthattheself-healingcapacityofconcretecuringinsodiumcarbonatesolutionwasmuchbetterthanthatofconcretecuringinwater.Indifferentconcentrationsofsodiumcarbonatesolution,theearlyrisingrateofstrengthandultrasonicvelocityofconcretesamplewashigh,alongwiththeprolongationofcuringage,therisingrateofstrengthandultrasonicvelocityleveledoff.Concretecuringinthe6%sodiumcarbonatesolutionshowedthebestself-healingperformanceanditscompressivestrengthrecoveredcompletelyinthecuringageof49days,andthestrengthrestorationratiowas106.1%inthecuringageof60days.Thestrengthrestorationratioofconcretecuringin2%sodiumcarbonatesolutionwasonly73.5%inthecuringageof60days.4%sodiumcarbonatesolutionshowedamiddleself-healingperformance.Theamountandsizeofhydrationproducts,suchasC-S-Hgelandcalciumcarbonate,increasedwiththeincreaseofsodiumcarbonatesolutionconcentration.Thesehydrationproductsmadethecrackhealedgraduallythroughfillingactionandcementationaction.