CAJ | 학술논문

基于大体积混凝土内部的温度变化,利用27 Al魔角旋转核磁共振(27 Al MAS NMR)结合去卷积技术,研究变温下 SO2-4对水泥硬化浆体中 Al3+配位分布的影响。结果表明,变温的高温阶段促进 AFt、TAH(third aluminum hydrate)和掺杂在 C-S-H 结构中(C-S-A-H)的四配位铝(Al[4])向 AFm 转化；降温阶段促进TAH 生成,利于AFm和C-S-A-H 中Al[4]向AFt转化；而变温后20℃常温不仅利于 AFt 向AFm转化,TAH 向Al[4]转变,而且利于 Al[4]进入高钙硅比(Ca/Si)C-S-H 结构。在5% Na2 SO4溶液中,SO2-4在侵蚀3 d时首先对 AFm 侵蚀,对 TAH 和C-S-A-H 中 Al [4]侵蚀作用较小；变温过程的高温加快SO2-4对AFm和TAH 的侵蚀,并且对C-S-A-H 凝胶有脱铝作用；变温后20℃常温有利于 C-S-H 凝胶与硫酸根竞争 Al[4],低 Ca/Si 的 C-S-A-H 凝胶具有较强的抗SO2-4脱铝能力。
기우대체적혼응토내부적온도변화,이용27 Al마각선전핵자공진(27 Al MAS NMR)결합거권적기술,연구변온하 SO2-4대수니경화장체중 Al3+배위분포적영향。결과표명,변온적고온계단촉진 AFt、TAH(third aluminum hydrate)화참잡재 C-S-H 결구중(C-S-A-H)적사배위려(Al[4])향 AFm 전화；강온계단촉진TAH 생성,리우AFm화C-S-A-H 중Al[4]향AFt전화；이변온후20℃상온불부리우 AFt 향AFm전화,TAH 향Al[4]전변,이차리우 Al[4]진입고개규비(Ca/Si)C-S-H 결구。재5% Na2 SO4용액중,SO2-4재침식3 d시수선대 AFm 침식,대 TAH 화C-S-A-H 중 Al [4]침식작용교소；변온과정적고온가쾌SO2-4대AFm화TAH 적침식,병차대C-S-A-H 응효유탈려작용；변온후20℃상온유리우 C-S-H 응효여류산근경쟁 Al[4],저 Ca/Si 적 C-S-A-H 응효구유교강적항SO2-4탈려능력。
Based on the temperature variation in the interior of mass concrete,the effect of sulfate ions on distri-bution of Al3+ coordination in hardened cement pastes at variable temperature were investigated by 27 Al magic angle spinning (MAS)nuclear magnetic resonance(NMR)with deconvolution technique.The results indicated that the high temperature during the variable temperature process promoted ettringite (AFt),third aluminum hydrate (TAH)and tetrahedral coordination Al3+(Al[4])incorporated in C-S-H structure transformed to mo-nosulphate (AFm).And the decreasing temperature process promoted the formation of TAH,and was benefi-cial to the AFm and Al[4]transforming to the AFt.But the normal temperature of 20 ℃ was not only advanta-geous for transformation from AFt to AFm,and from TAH to Al[4],but also for Al[4]entering into the C-S-H structure with high Ca/Si.However,in 5% Na2 SO4 solution,firstly,the AFt was formed due to AFm at-tacked by the sulfate ions,and the effect of sulfate ions on the TAH and tetrahedral coordination Al3+ in C-S-H structure was less at 3 d.The variation temperature speeded up the corrosion of sulfate ions for TAH and Al [4],and there was a dealuminization of the sulfate ions for C-S-A-H gels.Moreover,the normal temperature of 20 ℃ was beneficial to competition of C-S-H gels with sulfate ions for the Al[4],and the sulfate ions resist-ance of dealuminization of C-S-A-H gels with low Ca/Si was stronger.