[中文]粉煤灰是一种低成本的物质。在砂浆和混泥土产品中使用粉煤灰既经济又实惠。碱激活化类型F粉煤灰是在85 摄氏温度下,把灰加入到高度碱性溶液(PH>13),固化结果粘贴生成固体物质,从而得到碱激活类型F粉煤灰。比起普通波特兰水泥,碱性水泥不仅耐火性好,而且具有较高的耐硫酸盐腐蚀,并且因为碱性反应而不易扩张。除了秉承钢筋性好,稳定性强,高耐火性和导热系数低等特点,因此在激进的环境中, 承受出色的耐久性能力令人信服。人们认为,钢筋腐蚀是导致钢筋混凝土结构倒塌的主要原因。对于扩展钢筋水泥结构的耐久性来说,钢筋钝化的FA迫击炮容量是一个很重要的争议。大概情况下,假定它的高碱度(即便高于OPC砂浆)和在Pourbaix 图上的位置,跟激化FA相比较,碱性混凝土可以限制钢筋腐蚀到可以忽略的水平。一旦达到钝化能力和被动度永久性,将会依靠性质和粘合剂用量,活化剂使用,以及环境状况。[/中文]
[外文]Fly ash (FA) is a low-cost material which can be economically
beneficial if used in mortar and concrete production [1]. Alkali acti-
vation of type F fly ash is achieved by mixing the ash with highly
alkaline solutions (pH > 13) and curing the resulting paste at about
85 ?C to produce a solid material [2–4]. Alkaline cements show bet-
ter durability than ordinary Portland cement (OPC) thanks to their
high resistance to sulphate attack and are less prone to expansion
due to alkali–silica reactions [5]. Besides adhering extraordinarily
well to reinforcing steel, they also feature high-volume stability,
high fire resistance and low thermal conductivity, and thus con-
ceivably afford excellent durability in aggressive environments.
Considering that rebar corrosion is the main cause of reinforced
concrete structure (RCS) failure [6,7], the capacity of FA mortars
to passivate steel rebars may be a very important issue to extend
RCS durability. Presumably, given its high alkalinity (even higher
than OPC mortar) and concomitant position on the Pourbaix dia-
gram, alkaline concrete prepared with activated FA should limit
rebar corrosion to negligible levels. The passivating capacity and
permanence of the passive state once reached will depend on the
nature and dosage of the binder, on the type of activator use[/外文]
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