本文選題：納米氧化鋁粉　切入點(diǎn)：鋁酸鈣水泥　出處：《鄭州大學(xué)》2017年碩士論文

【摘要】：鋁酸鈣水泥(CAC)結(jié)合澆注料的中溫強(qiáng)度較低,首次升溫過程容易產(chǎn)生剝落現(xiàn)象,大大降低了澆注料高溫使用可靠性。引入表面活性較高的納米氧化粉,有助于促進(jìn)澆注料基質(zhì)燒結(jié),提高中溫及高溫強(qiáng)度。目前關(guān)于納米粉氧化鋁粉在澆注料中的燒結(jié)行為研究較少,而且納米氧化鋁粉對鋁酸鈣水泥水化速度、對澆注料的流動性和工作時間的研究尚未見到研究報道。因此本工作研究了納米氧化鋁粉對鋁酸鈣水泥不同溫度下水化行為的影響,還探究了納米氧化鋁粉對氧化鋁微粉以及澆注料基質(zhì)燒結(jié)性能的影響。結(jié)果表明:(1)在10~40°C時,氧化鋁凝膠粉和氧化鋁納米粉促進(jìn)了鋁酸鈣水泥的水化。氧化鋁凝膠粉雖未改變鋁酸鈣水泥凈漿10~30°C的異常凝結(jié)行為,但在30°C時,水化速度明顯變快。含氧化鋁納米粉的鋁酸鈣水泥混合物凈漿在30~40°C時,異常凝結(jié)行為消失。氧化鋁納米粉改變了這種異常凝結(jié)的現(xiàn)象�？赡芤�?yàn)檠趸X納米粉和氧化鋁凝膠粉提供水化產(chǎn)物成核點(diǎn),而促進(jìn)水泥水化。(2)在10~40°C時,氧化鋁凝膠粉和氧化鋁納米粉有利于水化產(chǎn)物的形成,且水化產(chǎn)物的生成量也比較多,促進(jìn)了鋁酸鈣水泥凈漿的水化,其中氧化鋁納米粉的促進(jìn)效果更強(qiáng),生成的水化產(chǎn)物結(jié)晶性更好。因?yàn)檠趸X納米粉比氧化鋁凝膠粉分散性更好,提供水泥水化有效成核面積比氧化鋁凝膠粉更大,從而更利于促進(jìn)水泥水化。(3)養(yǎng)護(hù)溫度為40°C時,添加5%氧化鋁凝膠粉和5%氧化鋁納米粉的鋁酸鈣水泥試樣水化放熱最高峰的時間分別為40 min和30 min,純鋁酸鈣水泥凈漿水化放熱最高峰的時間為3 h,明顯促進(jìn)水泥水化,會大大縮短澆注料可施工時間而不利于施工。因此,當(dāng)施工環(huán)境溫度較高為40°C時,不適于添加氧化鋁納米粉和氧化鋁凝膠粉。(4)氧化鋁凝膠粉和氧化鋁納米粉的比表面積大、活性高促進(jìn)了氧化鋁微粉在1200~1500°C的燒結(jié)。二者的比表面積不同,團(tuán)聚程度不同,最佳加入量也不同。僅加入5%氧化鋁凝膠粉含量時,試樣抗折強(qiáng)度最大,為88.67 MPa。隨著加入量的增加,試樣的抗折強(qiáng)度降低,這是較多的氧化鋁凝膠粉容易團(tuán)聚的緣故。而氧化鋁納米粉其分散性比氧化鋁凝膠粉好,其加入量可以增加到30%,試樣抗折強(qiáng)度最大,為86.67 MPa。(5)氧化鋁凝膠粉和氧化鋁納米粉有利于澆注料基質(zhì)的燒結(jié)。溫度為1600°C時,澆注料基質(zhì)試樣的抗折強(qiáng)度為100 MPa。氧化鋁凝膠粉比表面積大,容易團(tuán)聚,加入量不易太大。試樣中氧化鋁凝膠粉含量為5%時抗折強(qiáng)度最大,為118.25 MPa;隨著加入量的增加,氧化鋁凝膠粉團(tuán)聚嚴(yán)重,強(qiáng)度下降。而氧化鋁納米粉分散性好,可以適當(dāng)增加其加入量。試樣氧化鋁納米粉的含量為30%時抗折強(qiáng)度最大,為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 擄C, but at 30 擄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 擄C, 40 擄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 擄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 擄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 擄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，

本文編號：1699706