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《膨脹劑和含水率對(duì)預(yù)拌補(bǔ)償收縮混凝土微觀結(jié)構(gòu)的影響》由會(huì)員上傳分享,免費(fèi)在線閱讀,更多相關(guān)內(nèi)容在應(yīng)用文檔-天天文庫(kù)。
1、第10卷第13期2015年7月中國(guó)科技論文CHINASCIENCEPAPERVol.10No.13Jul.2015膨脹劑和含水率對(duì)預(yù)拌補(bǔ)償收縮混凝土微觀結(jié)構(gòu)的影響張陽(yáng)陽(yáng),馬芹永(安徽理工大學(xué)礦山地下工程教育部工程研究中心,安徽淮南232001)摘要:為研究膨脹劑和干拌混合料含水率對(duì)預(yù)拌補(bǔ)償收縮混凝土微觀結(jié)構(gòu)的影響,進(jìn)行了貯存期為7d,5種膨脹劑摻量(0%、4%、6%、8%和10%),3種含水率(0.5%、1.0%和1.5%)情況下的預(yù)拌料混凝土微觀結(jié)構(gòu)試驗(yàn)。結(jié)果表明:當(dāng)膨脹劑摻量為0%到6%時(shí),隨著膨脹劑摻量的增加,針棒狀鈣礬
2、石AFt晶體在混凝土內(nèi)部的孔洞和微裂縫中不斷生長(zhǎng),且和C-S-H凝膠逐漸搭接在一起形成相互交錯(cuò)的網(wǎng)狀結(jié)構(gòu),C-S-H凝膠和Ca(OH)2晶體間構(gòu)成的微界面及內(nèi)部大量空隙被填實(shí),混凝土孔隙率減小,形成了較為均勻密實(shí)的連續(xù)體;當(dāng)膨脹劑摻量為8%和10%時(shí),在混凝土內(nèi)部除致密的膠凝連續(xù)體和原有的裂縫外,會(huì)產(chǎn)生由于膨脹性能過(guò)大引起的新微裂縫,且隨膨脹劑摻量的增加,新微裂縫的尺寸也有所增大,導(dǎo)致混凝土的孔隙率增加。隨著干拌混合料含水率的增加,混凝土中凝膠數(shù)量相對(duì)減少,且和Ca(OH)2晶體的黏結(jié)性逐漸下降,孔洞的數(shù)量和尺寸增加,導(dǎo)致孔隙率增
3、大,密實(shí)度下降。關(guān)鍵詞:補(bǔ)償收縮混凝土;預(yù)拌料混凝土;膨脹劑;含水率;微觀結(jié)構(gòu);孔隙率中圖分類號(hào):TU528.55文獻(xiàn)標(biāo)志碼:A文章編號(hào):20952783(2015)13153504Effectsofexpansiveagentsandwatercontentsonmicrostructureofready-mixedshrinkage-compensatingconcreteZhangYangyang,MaQinyong(UndergroundEngineeringResearchCenterforMiningofMinistr
4、yofEducation,AnhuiUniversityofScienceandTechnology,Huainan,Anhui232001,China)Abstract:Inordertostudytheeffectoftheexpansiveagentdosagesandthesandmoisturecontentofdry-mixedmaterialsonthemicrostructureoftheready-mixedshrinkage-compensatingconcrete,anexperimentwasconduct
5、edonsampleswiththestorageperiodof7daysincluding5kindsofexpansiveagentdosages(0%,4%,6%,8%and10%)and3kindsofsandmoisturecon-tents(0.5%,1.0%and1.5%).Theresultsshowthat,needlelikecrystalsofettringite(AFt)constantlygrewintheholesandmicrocrackswithintheconcreteandgraduallyl
6、appedtogetherwiththeC-S-Hgeltogenerateaninterlacednetworkstructurewiththeincreaseofexpansiveagentdosagesfrom0%to6%.ThemicrointerfacebetweentheC-S-HgelandCa(OH)2crystalandlargenumbersofinternalvoidsinthemicrointerfacewerefilled,leadingtodecreasingporosityoftheconcretea
7、ndgeneratingarelativelyuniformhomogeneousmatter.Whentheexpansiveagentdosagewasequalto8%or10%,apartfromthedensegelcontinuumandinitialcracksintheconcrete,newmicrocrackswereinducedduetotoomuchexpansivepropertyintheconcrete.Moreoverthesizeofthesenewcracksincreasedgraduall
8、ywiththeincreasingexpansiveagentdosages,whichresultedinthein-creaseoftheporosityandthedecreaseofthecompactness.Withtheincrea