高强低吸水发泡水泥的制备及性能研究

发布时间：2018-05-22 12:24

本文选题：发泡水泥 + 抗压强度　；参考：《山东科技大学》2017年硕士论文

【摘要】：发泡水泥作为一种节能型的新型建材,具有质轻、保温隔热、防火性能优越等特点,但是发泡水泥特殊的结构使它的抗压强度低、防水性能差,制约了发泡水泥的推广和应用。因此,需要优化发泡水泥的抗压强度和防水性能,以利于发泡水泥的发展和应用。本文通过纤维增强、羧甲基纤维素钠(CMC)增强和化学外加剂增强的方法,针对不同增强方法对发泡水泥的强度影响规律进行了研究;采用添加防水剂和减水剂的方法,考察了防水剂和减水剂对发泡水泥的吸水性能的影响。纤维增强实验结果表明:在纤维的长度相同时,聚丙烯纤维、玻璃纤维和碳纤维的最佳掺量分别为0.4%、0.4%和0.2%,在最佳掺量条件下,掺加聚丙烯纤维的试样的性能最优;在同种纤维相同掺量时,纤维长度较短时,对发泡水泥的增强效果较显著。实验最终确定添加0.4%的长度为6mm的聚丙烯纤维,此时发泡水泥的抗压强度为1.20MPa,与空白试样相比提高了 94%。CMC增强实验结果表明:不同温度的CMC溶液对发泡水泥的抗压强度均有不同程度的提高。掺入25℃℃的CMC溶液可获得的最佳抗压强度为1.06MPa,掺入50℃CMC溶液可获得的最佳抗压强度为1.26MPa,分别比空白试样提高71%和103%,此时CMC的最佳掺量分别为0.085‰和0.069‰。CMC在发泡水泥体系中,一方面可以促进水泥水化和粉煤灰发挥火山灰效应,另一方面能够改变发泡水泥的微观形貌,使孔壁结构更为致密。化学外加剂增强试验结果表明:硫酸氢钠对发泡水泥抗压强度影响比较大,硫脲的影响次之,而硫化钠对发泡水泥的抗压强度几乎不存在影响。当硫酸氢钠掺量为0.1%时,试样的28d抗压强度达到最大1.13MPa,较空白试样提高了 30%。硫酸氢钠的加入有利于水泥的水化,减少了不利于强度的Ca(OH)2的含量,水化产物彼此交叉连生形成网状结构,使发泡水泥的骨架致密,提高了发泡水泥的强度。防水剂对发泡水泥吸水性能的影响研究表明:防水剂对发泡水泥的吸水率的效果不明显,防水剂的用量从1%增加到5%时,吸水率从38%降低到34%,仅降低了 4%,而且防水剂使发泡水泥的抗压强度降低,不适合用在本实验的发泡水泥体系中。减水剂对发泡水泥吸水性能的影响研究表明:减水剂可以有效降低发泡水泥的吸水率,当萘系减水剂掺量从0.1%增加到0.9%时,发泡水泥的吸水率从38.4%降低到22%,在最佳掺量0.9%时,相比于空白试样降低了 43%,而且在此用量下,萘系减水剂对发泡水泥的抗压强度没有危害;而聚羧酸减水剂的掺量在相同范围变化时,发泡水泥的吸水率从38.4%降低到35%,效果不及萘系减水剂。根据以上研究,得到具有高强度和低吸水率的发泡水泥的配方:主材采用70%水泥+30%粉煤灰,其他添加剂为:双氧水5%、6mm聚丙烯纤维0.4%、硬脂酸钙0.8%、碳酸锂0.08%、硫酸氢钠0.1%、CMC0.069‰、萘系减水剂0.9%(占主材的重量百分数),水灰比0.4。制备的发泡水泥的抗压强度为1.26MPa,干密度为286kg/m3,吸水率为22%,导热系数0.045W/(m·K),与JC/T266《泡沫混凝土》中A03级泡沫混凝土的技术指标相比,用该配方制备的发泡水泥具有高强度、低吸水率的优点。此外,为了扩大原材料的来源,降低发泡水泥的生产成本,本文还在此配方的基础上,用矿渣替代部分水泥,用尾矿替代部分粉煤灰,研究了矿渣和尾矿对发泡水泥性能的影响规律及作用机理,研究结果表明:矿渣取代水泥对发泡水泥的抗压强度有不利影响;但是,采用细磨硅质尾矿取代部分粉煤灰,则会在一定程度上提高发泡水泥的抗压强度,并且抗压强度会随着尾矿细度的提高而增大。根据以上研究得到由50%的水泥、20%的粉煤灰、20%的矿渣和10%的比表面积为1161.7m2/kg的尾矿组成的发泡水泥主材体系,制备出的发泡水泥的抗压强度为1.19MPa,干密度为272kg/m3,吸水率为27%,导热系数为0.049W/(m·K),其性能优于JC/T266《泡沫混凝土》中A03级泡沫混凝土的技术指标。
[Abstract]:As a new type of energy-saving building materials, foamed cement has the characteristics of light quality, heat insulation and excellent fire resistance. But the special structure of foamed cement makes it low compressive strength and poor waterproof performance, which restricts the popularization and application of foamed cement. Therefore, it is necessary to optimize the compressive strength and waterproof performance of the cement, in order to make the bubble water. The development and application of mud. In this paper, the effect of different reinforcement methods on the strength of foamed cement was studied through fiber reinforcement, CMC enhancement and chemical admixtures, and the effects of waterproofing agent and water reducing agent on the water absorption of foamed cement were investigated by adding water repellent and water reducing agent. The results of fiber reinforced experiment show that the optimum mixing amount of polypropylene fiber, glass fiber and carbon fiber is 0.4%, 0.4% and 0.2% respectively when the fiber length is the same. Under the optimal dosage condition, the performance of the sample with polypropylene fiber is the best. When the same amount of fiber is the same, the fiber length is shorter, the enhancement effect on the foamed cement is obtained. The experiment finally confirmed the addition of 0.4% polypropylene fiber with a length of 6mm, at this time the compressive strength of the foamed cement was 1.20MPa. Compared with the blank sample, the 94%.CMC enhancement experimental results showed that the compressive strength of the foamed cement at different temperatures was improved in different degrees. The CMC solution added to 25 C was obtained. The optimum compressive strength is 1.06MPa, the best compressive strength of CMC solution added to 50 C is 1.26MPa, which is 71% and 103% higher than that of blank sample. At this time, the best dosage of CMC is 0.085 per thousand and 0.069 per 1000.CMC respectively in the foam cement system. On the one hand, the cement hydration and the fly ash can be promoted to play the volcanic ash effect, on the other hand, the effect can be changed. The microstructure of the foamed cement makes the pore wall structure more compact. The results of the chemical admixture enhancement test show that sodium bisulfate has a great influence on the compressive strength of the foamed cement, the effect of thiourea is the second, and the sodium sulfide has little effect on the compressive strength of the foamed cement. The 28d compressive strength of the sample is reached when the dosage of sodium hydrogen sulphate is 0.1%. To the maximum 1.13MPa, the addition of 30%. sodium bisulfate in the blank sample increases the hydration of cement and reduces the content of Ca (OH) 2, which is not good for strength. The hydration products cross together to form a network structure, which makes the skeleton of the foamed cement dense and improves the strength of the foamed cement. The effect of the waterproof agent on the water absorption of the foamed cement is studied. The results showed that the effect of waterproofing agent on the water absorption of foamed cement was not obvious. When the dosage of waterproofing agent increased from 1% to 5%, the water absorption rate was reduced from 38% to 34%, only 4%, and the waterproof agent reduced the compressive strength of the foamed cement. It was not suitable for the foaming cement system of this experiment. The influence of water reducing agent on the water absorption of the foaming cement was studied. Water reducing agent can effectively reduce the water absorption of foamed cement. When the dosage of naphthalene superplasticizer is increased from 0.1% to 0.9%, the water absorption of foamed cement is reduced from 38.4% to 22%. When the optimum dosage is 0.9%, it is 43% lower than that of the blank sample. Moreover, the naphthalene water reducing agent has no harm to the compressive strength of the foamed cement; and polycarboxylic acid When the amount of water reducing agent is changed in the same range, the water absorption rate of the foamed cement is reduced from 38.4% to 35%, and the effect is less than the naphthalene water reducing agent. According to the above study, the formula of foamed cement with high strength and low water absorption is obtained: the main material is 70% cement +30% fly ash, the other additives are hydrogen peroxide 5%, 6mm polypropylene fiber 0.4%, calcium stearate 0. 8%, lithium carbonate 0.08%, sodium bisulfate 0.1%, CMC0.069 per thousand and naphthalene water reducer 0.9% (the weight percentage of the main material). The compressive strength of the foamed cement prepared by water cement ratio 0.4. is 1.26MPa, the dry density is 286kg/m3, the water absorption rate is 22%, the thermal conductivity 0.045W/ (m K), compared with the technical indexes of JC/T266 < foam concrete > A03 foam concrete. The foaming cement prepared by formula has the advantages of high strength and low water absorption. In addition, in order to expand the source of raw materials and reduce the production cost of foamed cement, based on this formula, the slag replaced some cement and the tailings replaced some fly ash, and the influence law and effect of slag and tailings on the performance of foamed cement were studied. The results show that the slag replacement cement has a negative effect on the compressive strength of the foamed cement. However, the use of fine grinding silica tailings to replace some fly ash will increase the compressive strength of the foamed cement to a certain extent, and the compressive strength will increase with the increase of the fineness of the tailings. According to the above study, 50% cement is obtained. 20% of fly ash, 20% slag and 10% foam cement main system with specific surface area of 1161.7m2/kg, the compressive strength of the prepared foamed cement is 1.19MPa, the dry density is 272kg/m3, the water absorption is 27%, the thermal conductivity is 0.049W/ (M. K). The performance is better than the technology of JC /T266< foam concrete > A03 foam concrete technology. Mark.
【学位授予单位】：山东科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ172.1

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