不同离子对混凝土碱硅酸反应影响的研究进展

Research Progress on the Effects of Different Ions on Alkali-Silica Reaction of Concrete

混凝土的碱硅酸反应(Alkali-silica reaction,ASR)本质上是孔溶液中的离子、水分子与骨料中活性二氧化硅的反应。根据不同离子对ASR的影响效果,可将离子分为碱离子(Na^(+)、K^(+)和OH-)、锂离子和铝离子、钙离子。碱离子(Na^(+)、K^(+)和OH^(-))促进混凝土的碱硅酸反应,导致混凝土发生更严重的膨胀性破坏。Al^(3+)和Li^(+)减缓混凝土碱硅酸反应造成的膨胀性破坏;Ca^(2+)起到的作用与n(Ca)/n(Si)(物质的量比)密切相关,当n(Ca)/n(Si)<0.2时,Ca^(2+)对ASR起促进作用;当n(Ca)/n(Si)≥0.2时,Ca^(2+)对ASR起抑制作用。本文首先介绍了ASR反应产物的最新研究进展,包括ASR产物的种类、微观形貌、原子结构及水稳定性,综述了这些离子对ASR反应过程、ASR产物组成、ASR产物结晶性能及膨胀性的影响,展望了不同离子对混凝土ASR影响的未来研究方向。

Alkali-silica reaction(ASR)of concrete is essentially the reaction of ions and water molecules in the pore solution with active silica in the aggregate.According to the influence of different ions on ASR,ions can be divided into alkali ions(Na^(+),K^(+)and OH-),lithium ion and aluminum ion,calcium ion.Alkali ions promote the alkali-silica reaction of concrete,resulting in more severe expansive damage to concrete.Lithium and aluminum ions slow down the expansive damage caused by alkali-silica reaction of concrete.The role of Ca^(2+)is closely related to n(Ca)/n(Si)(molar ratio).When the n(Ca)/n(Si)<0.2,Ca^(2+)promotes ASR.When the n(Ca)/n(Si)≥0.2,Ca^(2+)inhibits ASR.Firstly,the latest research progresses of ASR products are introduced,including the types,micro morphology,atomic structure and water stability of ASR pro-ducts.Then,influences of these ions on the ASR process,the composition of ASR products,the crystallization properties and expansion of ASR products are reviewed.Finally,the future research direction of the influence of different ions on ASR is prospected.