纳米氧化铝粉对铝酸钙水泥水化及浇注料基质烧结性能的影响

发布时间：2018-04-02 09:11

  本文选题：纳米氧化铝粉　切入点：铝酸钙水泥　出处：《郑州大学》2017年硕士论文

【摘要】：铝酸钙水泥(CAC)结合浇注料的中温强度较低,首次升温过程容易产生剥落现象,大大降低了浇注料高温使用可靠性。引入表面活性较高的纳米氧化粉,有助于促进浇注料基质烧结,提高中温及高温强度。目前关于纳米粉氧化铝粉在浇注料中的烧结行为研究较少,而且纳米氧化铝粉对铝酸钙水泥水化速度、对浇注料的流动性和工作时间的研究尚未见到研究报道。因此本工作研究了纳米氧化铝粉对铝酸钙水泥不同温度下水化行为的影响,还探究了纳米氧化铝粉对氧化铝微粉以及浇注料基质烧结性能的影响。结果表明:(1)在10~40°C时,氧化铝凝胶粉和氧化铝纳米粉促进了铝酸钙水泥的水化。氧化铝凝胶粉虽未改变铝酸钙水泥净浆10~30°C的异常凝结行为,但在30°C时,水化速度明显变快。含氧化铝纳米粉的铝酸钙水泥混合物净浆在30~40°C时,异常凝结行为消失。氧化铝纳米粉改变了这种异常凝结的现象。可能因为氧化铝纳米粉和氧化铝凝胶粉提供水化产物成核点,而促进水泥水化。(2)在10~40°C时,氧化铝凝胶粉和氧化铝纳米粉有利于水化产物的形成,且水化产物的生成量也比较多,促进了铝酸钙水泥净浆的水化,其中氧化铝纳米粉的促进效果更强,生成的水化产物结晶性更好。因为氧化铝纳米粉比氧化铝凝胶粉分散性更好,提供水泥水化有效成核面积比氧化铝凝胶粉更大,从而更利于促进水泥水化。(3)养护温度为40°C时,添加5%氧化铝凝胶粉和5%氧化铝纳米粉的铝酸钙水泥试样水化放热最高峰的时间分别为40 min和30 min,纯铝酸钙水泥净浆水化放热最高峰的时间为3 h,明显促进水泥水化,会大大缩短浇注料可施工时间而不利于施工。因此,当施工环境温度较高为40°C时,不适于添加氧化铝纳米粉和氧化铝凝胶粉。(4)氧化铝凝胶粉和氧化铝纳米粉的比表面积大、活性高促进了氧化铝微粉在1200~1500°C的烧结。二者的比表面积不同,团聚程度不同,最佳加入量也不同。仅加入5%氧化铝凝胶粉含量时,试样抗折强度最大,为88.67 MPa。随着加入量的增加,试样的抗折强度降低,这是较多的氧化铝凝胶粉容易团聚的缘故。而氧化铝纳米粉其分散性比氧化铝凝胶粉好,其加入量可以增加到30%,试样抗折强度最大,为86.67 MPa。(5)氧化铝凝胶粉和氧化铝纳米粉有利于浇注料基质的烧结。温度为1600°C时,浇注料基质试样的抗折强度为100 MPa。氧化铝凝胶粉比表面积大,容易团聚,加入量不易太大。试样中氧化铝凝胶粉含量为5%时抗折强度最大,为118.25 MPa;随着加入量的增加,氧化铝凝胶粉团聚严重,强度下降。而氧化铝纳米粉分散性好,可以适当增加其加入量。试样氧化铝纳米粉的含量为30%时抗折强度最大,为120 MPa。
[Abstract]:The calcium aluminate cement (CAC) binder has low moderate temperature strength, and the phenomenon of spalling is easy to occur during the first heating process, which greatly reduces the reliability of the castable at high temperature, and introduces the nanometer oxidized powder with high surface activity. It is helpful to promote the sintering of castable matrix and improve the strength of medium temperature and high temperature. At present, there is little research on the sintering behavior of nano-alumina powder in castable, and the hydration rate of nano-alumina powder to calcium aluminate cement, The study on the fluidity and working time of castable has not been reported. Therefore, the effect of nano-alumina powder on the hydration behavior of calcium aluminate cement at different temperatures has been studied. The effect of nanometer alumina powder on sintering properties of alumina powder and castable matrix was also investigated. Alumina gel powder and alumina nano-powder promoted the hydration of calcium aluminate cement. Although alumina gel powder did not change the abnormal condensation behavior of calcium aluminate cement paste at 1030 掳C, but at 30 掳C, alumina gel powder promoted the hydration of calcium aluminate cement. The hydration rate of calcium aluminate cement mixture containing nanometer alumina powder is obviously faster. At 30 掳C, 40 掳C, The abnormal condensation behavior disappears. The phenomenon of abnormal condensation is changed by alumina nano-powder. It may be that the hydration point of hydration products is provided by alumina nanometer powder and alumina gel powder, and that the hydration of cement is promoted at 1040 掳C, Alumina gel powder and alumina nano-powder are favorable to the formation of hydration products, and the amount of hydration products is more, which promotes the hydration of calcium aluminate cement paste. The resulting hydration product has better crystallinity because the alumina nano-powder is more dispersive than the alumina gel powder, and the effective nucleation area of providing cement hydration is larger than that of the alumina gel powder, which is more conducive to promoting cement hydration at 40 掳C curing temperature. The peak time of hydration heat release of calcium aluminate cement samples added 5% alumina gel powder and 5% alumina nanometer powder was 40 min and 30 min, respectively, and that of pure calcium aluminate cement was 3 h, which obviously promoted the hydration of cement. It will greatly shorten the construction time of the castable and is not conducive to the construction. Therefore, when the construction environment temperature is higher than 40 掳C, it is not suitable to add alumina nanometer powder and alumina gel powder. 4) the specific surface area of alumina gel powder and alumina nanometer powder is large. The high activity promoted the sintering of alumina powder at 1200 鈩，

本文编号：1699706