国外用普通硅酸盐水泥熟料、二水石膏和在600～700℃煅烧过的硅化明矾制造不透水膨胀硅酸盐水泥。熟料的矿物组成为:C_3S 53%,C_2S 20%,C_3A 8%,C_4AF 15%。硅化明矾在600～700℃煅烧后得到的产物为具有反应能力的氧化铝、硫酸铝和少量的硫酸钾、钠。这些化合物能够与石膏、氢氧化钙和熟料其他水化产物作用而得到膨胀水泥。经过多次试验确定,原料最恰当的配比为:82%水泥熟料;10%二水石膏;8%在600～700℃煅烧过的硅化明矾。用这种膨胀水泥 Overseas use of ordinary portland cement clinker, dihydrate gypsum and siliconized alum calcined at 600-700 °C to produce water-impermeable expanded portland cement. The mineral composition of clinker is: C_3S 53%, C_2S 20%, C_3A 8%, C_4AF 15%. The product obtained after the calcined alum was calcined at 600-700° C. is a reaction alumina, aluminum sulfate, and a small amount of potassium sulfate and sodium sulfate. These compounds can interact with gypsum, calcium hydroxide and other hydration products of the clinker to obtain expanded cement. After several tests, it was determined that the most appropriate ratio of raw materials was: 82% cement clinker; 10% dihydrate gypsum; 8% siliconized alum calcined at 600-700°C. Use this kind of expansive cement