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当混凝土浸入在含硫酸盐的水中,一般随时间推移而劣化,并最终导致强度降低。据证明因粉煤灰取代部分波特兰水泥,能有效提高混凝土的耐硫酸盐性,但这要取决于水泥和粉煤灰的物理化学性能。硫酸盐导致混凝土劣化主要是由于石膏和钙矾石形成下的膨胀所致,其原因是硫酸盐离子与混凝土中氢氧化钙水化物产生反应。因此可预料按适宜配比设计的高掺量粉煤灰混凝土充分养护后,具有良好的耐硫酸盐侵蚀性。这里因为其孔隙结构细小而连续,生成的氢氧化钙数量很小,但硫酸盐导致混凝土劣化竟是一种复杂的物理化学过程,用高掺量粉煤灰取代水泥提高混凝土耐硫酸盐性的机理目前尚未彻底弄清。为此日本就高掺
When concrete is immersed in sulphate-containing water, it generally degrades with time and eventually leads to a decrease in strength. It has been proved that the replacement of part of Portland cement with fly ash can effectively improve the sulfate resistance of concrete, but this depends on the physical and chemical properties of cement and fly ash. Sulfate causes concrete deterioration mainly due to the expansion of gypsum and ettringite, which is caused by the reaction of sulfate ions with calcium hydroxide hydrate in concrete. Therefore, it can be expected that the high-volume fly ash concrete designed according to the proper proportioning ratio will have good resistance to sulphate corrosion after fully curing. Because of its fine and continuous pore structure, the amount of calcium hydroxide produced is small, but the degradation of concrete caused by sulfate is actually a complex physical chemical process. The replacement of cement with high volume of fly ash improves the sulfate resistance of concrete. The mechanism has not yet been thoroughly understood. For this reason, Japan is highly adulterated