本文選題：改性硫氧鎂水泥　切入點：稻殼　出處：《哈爾濱工業(yè)大學》2017年碩士論文

【摘要】：硫氧鎂水泥是一種由輕燒氧化鎂粉與適當濃度的硫酸鎂溶液混合攪拌、凝結(jié)硬化而具有強度的無機膠凝材料。由于主要組份氧化鎂的煅燒溫度遠低于硅酸鹽水泥熟料的燒成溫度,具有能耗低、生產(chǎn)工藝簡單、成本低的優(yōu)點,同時,硫氧鎂水泥還具有良好的耐火性、耐熱性、密度低、導熱系數(shù)低、與不同材料的粘結(jié)力強等優(yōu)點。因此,作為一種新型無機膠凝材料,硫氧鎂水泥被廣泛的應用于制作輕質(zhì)墻板、耐火構(gòu)件、保溫隔熱板等。針對硫氧鎂水泥存在的強度偏低、耐水性差和收縮大等不足,本文首先研究了外摻少量檸檬酸、檸檬酸三鈉及硼酸對硫氧鎂水泥基本性能的改善效果;通過摻泡沫、稻殼及其兩者復摻的方式制備了硫氧鎂水泥輕質(zhì)材料,并研究了硫氧鎂水泥輕質(zhì)材料的強度、密度、導熱系數(shù)、干燥收縮以及干濕循環(huán)處理對其強度、體積變形的影響。并利用XRD、FTIR、DTA-TG、SEM及超景深顯微鏡測試方法分析了檸檬酸、檸檬酸三鈉及硼酸對硫氧鎂水泥的改性作用機理及硫氧鎂水泥輕質(zhì)材料的微觀結(jié)構(gòu)特征。結(jié)果表明:硫氧鎂水泥的強度隨著氧硫比的提高和水硫比的降低而提高。摻加檸檬酸、檸檬酸三鈉及硼酸后硫氧鎂水泥體系中生成了一種新的呈晶須狀的針棒狀晶體5·1·7相。由于這些針棒狀5·1·7相交叉連生,填充孔隙與裂縫,使原本疏松的結(jié)構(gòu)變得致密,從而改善硫氧鎂水泥石的強度、耐水性及干燥收縮性能。檸檬酸、檸檬酸三鈉、硼酸的最佳摻量分別為0.5%、2.5%、0.5%。其中,檸檬酸效果最好,可使硫氧鎂水泥的28d強度和軟化系數(shù)提高104.8%和61.09%,干燥收縮降低了32.81%。分別通過摻入泡沫、稻殼或兩者復摻制備了體積密度分別為450~1685kg/m3、759~1721kg/m3、544~1268kg/m3,28天抗壓強度分別為1.1~47.4MPa、2.9~70.4MPa、1.1~11.2MPa的硫氧鎂水泥基輕質(zhì)材料。所制備輕質(zhì)材料的抗壓強度、導熱系數(shù)分別隨著體積密度呈現(xiàn)指數(shù)函數(shù)和線性增長關(guān)系。硫氧鎂水泥基輕質(zhì)材料的干燥收縮值隨著泡沫摻加量出現(xiàn)先降低后增大的變化規(guī)律,而稻殼的摻入會增大干燥收縮。隨著干濕循環(huán)次數(shù)增多,硫氧鎂水泥基輕質(zhì)材料的強度不斷降低,收縮值不斷增大,但在稻殼摻量較少時反而出現(xiàn)膨脹現(xiàn)象。
[Abstract]:Magnesium sulfate cement is a mixture of light burned magnesium oxide powder and a suitable concentration of magnesium sulfate solution. Inorganic cementitious material with solidification and hardening. Because the calcination temperature of magnesium oxide, the main component, is far lower than that of Portland cement clinker, it has the advantages of low energy consumption, simple production process and low cost, at the same time, Magnesium sulfide cement also has the advantages of good fire resistance, heat resistance, low density, low thermal conductivity, strong adhesion to different materials, etc. Therefore, as a new inorganic cementitious material, Magnesium sulfide cement is widely used in making light wall panels, fire-resistant components, thermal insulation boards, etc. In view of the shortcomings of magnesium sulfide cement, such as low strength, poor water resistance and large shrinkage, a small amount of citric acid was added to the cement. The effects of trisodium citrate and boric acid on the basic properties of magnesium sulfide cement were studied. The effects of thermal conductivity, drying shrinkage and drying and wet cycle treatment on the strength and volume deformation of citric acid were analyzed by means of XRDX FTIR DTA-TGG SEM and hyperfield depth microscope. The mechanism of modification of magnesium sulfate cement by trisodium citrate and boric acid and the microstructure of magnesium sulfate cement were studied. The results showed that the strength of magnesium sulfate cement increased with the increase of oxygen / sulfur ratio and the decrease of water / sulfur ratio. A new whisker like needle-rod crystal 517 phase was formed in trisodium citrate and post-boric acid magnesium sulfide cement system. Due to the intersecting of these needle-rod phase 517, the original loose structure became compact due to the filling of pores and cracks. In order to improve the strength, water resistance and drying shrinkage of magnesium thio cement, the optimum content of citric acid, trisodium citrate and boric acid is 0.5%, 2.5% and 0.5% respectively. Among them, citric acid has the best effect. The 28d strength and softening coefficient of MgSO _ 2 cement were increased by 104.8% and 61.09%, and the drying shrinkage was reduced by 32.81%. The volume density of rice husk or both was 450,1685kg / m3759g / 1721kg / m3544 / 1268kg / m3 / m3 respectively. The compressive strength of the lightweight material was 1.1 ~ 47.4 MPA / m ~ (-1) ~ (-1) MPA respectively for 28 days, and the compressive strength of the prepared lightweight material was as follows: (1) mg _ (2) O _ (2) O _ (2) O _ (2) (mg _ (2) O _ (2)) (mg _ (2) O _ (2)) cement based material. The coefficient of thermal conductivity shows exponential function and linear increase with volume density. The drying shrinkage value of magnesium thiooxygen-based cement material decreases first and then increases with the increase of foam content. With the increase of dry-wet cycle times, the strength and shrinkage value of MgSO-based lightweight materials decreased and the shrinkage value increased, but when the amount of rice husk was less, the swelling phenomenon appeared.
【學位授予單位】：哈爾濱工業(yè)大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：TU528

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