辅助性胶凝材料粒度分布对水泥性能的影响

发布时间：2018-05-23 18:11

本文选题：粉煤灰 + Si-Mn矿渣　；参考：《西南科技大学》2017年硕士论文

【摘要】：大量的工业冶金废渣和燃煤飞灰具有潜在的水化活性,可作为辅助性胶凝材料生产复合水泥。传统的水泥行业都是采用熟料和辅助胶凝材料混合粉磨的方式制备复合水泥,由于熟料和辅助性胶凝材料易磨性差异大,造成水泥中各组分颗粒分布不合理,生产的复合水泥普遍存在早期强度低、凝结时间长和掺量低等问题。因此,研究辅助性胶凝材料粒度分布对水泥基材料性能的影响对于高效利用辅助性胶凝材料的水化活性、提高复合水泥性能非常重要。本文选取低钙粉煤灰和Si-Mn矿渣两种辅助性胶凝材料,通过旋风分级机分别将粉煤灰和Si-Mn矿渣精确分为细、中、粗(D5 0=5.0 6μm、15.6 3μm、3 5.0 1μm及D5 0=6.8 7μm、17.85μm、5 6.4μm)三个粒度区间。实验系统研究了粉煤灰和Si-Mn矿渣粒度、掺量对水泥砂浆力学性能和抗化学侵蚀性能的影响,并探讨了粉煤灰和Si-Mn矿渣粒度分布对水泥浆体水化产物、水化热、微观结构及化学侵蚀水化产物的影响。研究结论如下:(1)细粒度区间粉煤灰具有更高的Ca O、SO3、碱性氧化物和烧失量,不同粒度粉煤灰颗粒矿物组成基本一致;随着粉煤灰粒径的增加,表面光滑的球形颗粒减少。随着Si-Mn矿粉粒径的增加,Si O2、Al 2 O 3和S O3含量减少,而Ca O、Mn O、Ba O和Ti O2含量增加;石英和铝酸钙衍射峰强度随Si-Mn矿粉粒径增加而减小;越粗的Si-Mn矿渣颗粒由更多棱角分明、表面密实的颗粒组成。(2)粉煤灰水泥砂浆随着粉煤灰掺量的增加,各龄期强度都下降。而细粒度和中粒度Si-Mn矿渣水泥后期胶砂强度随着矿渣掺量增加而增加。随着粉煤灰和Si-Mn矿渣颗粒粒径的减小,水泥砂浆的各龄期强度增加。(3)粉煤灰和Si-Mn矿渣颗粒粒度对水泥浆体孔结构分布有显著影响,随着粉煤灰和Si-Mn矿渣粒径的减小,水泥浆体最可几孔径减小。(4)粉煤灰的掺入抑制了水泥水化放热速率和累积放热量,水化12 h左右,各水泥浆体出现了明显的加速期放热速率峰,且细粒度粉煤灰水泥的放热速率峰值明显高于中和粗粒度粉煤灰水泥浆体。水化12 0 h时,随着粉煤灰粒径减小,水泥浆体累积放热量都明显增加。S i-M n矿渣颗粒的掺入明显促进了水泥水化早期和水化后期的水化速率,且细粒度Si-Mn矿粉水泥具有更高的水化速率。水化24h内,硅酸盐水泥的累积放热量明显高于Si-Mn矿粉水泥,各粒度Si-Mn矿粉水泥累积放热曲线几乎一致。水化24h以后,Si-Mn矿渣水泥累积放热量大幅度增加且随Si-Mn矿粉粒径减小,水泥累积放热量增加幅度越大。(5)水化3d时,不同粒度粉煤灰和Si-Mn矿渣水泥浆体Ca(OH)2峰的强度无明显差异;水化60d时,随着粉煤灰和Si-Mn矿渣粒径的减小,Ca(OH)2峰的强度降低。细,中粒度区间Si-Mn矿渣和粉煤灰颗粒能有效降低Ca(OH)2含量。越细的粉煤灰颗粒和Si-Mn矿渣颗粒其表面生成的水化产物越多且粉煤灰颗粒表面水化生成的是一种C a/S i=0.7 4的C-S(A l)-H凝胶,S i-M n矿渣颗粒表面水化生成的是一种C a/S i=1.5 4的C-S(Al,M g)-H凝胶。(6)粉煤灰和Si-Mn矿渣水泥砂浆分别在硫酸盐中侵蚀28d和60 d时抗蚀系数达到最大值。水泥各龄期抗蚀系数随粉煤灰和S i-M n矿渣颗粒粒径的减小而增加,细、中粒度粉煤灰和Si-Mn颗粒能有效提高的水泥抗硫酸盐侵蚀性。粉煤灰水泥砂浆在模拟海水中,随侵蚀龄期的延长,其抗蚀系数持续增加,而Si-Mn矿渣水泥砂浆侵蚀28d龄期时抗蚀系数出现最大值。随着粉煤灰和Si-Mn矿渣粒径的减小,各龄期抗蚀系数都明显增加。(7)硫酸盐侵蚀初期,水泥浆体生成的石膏和钙矾石晶体衍射峰并不明显。侵蚀150d时,随着粉煤灰和Si-Mn矿渣粒度减小,水泥浆体中钙矾石和石膏衍射峰强度降低。水泥浆体在模拟海水中侵蚀产物主要为Ca4A l 2 O6 C l 2·1 0 H2O(Friedel’s盐),侵蚀2 8 d时,粉煤灰和Si-Mn矿渣粒度对侵蚀水化产物Friedel’s盐生成量无明显影响;侵蚀150d时,随着粉煤灰和Si-Mn矿渣粒径的减小,Friedel’s盐衍射峰强度降低。
[Abstract]:A large number of industrial metallurgical waste residue and Coal-fired Fly Ash have potential hydration activity, which can be used as auxiliary cementitious materials to produce composite cement. The traditional cement industry uses the mixture of clinker and auxiliary cementitious material to make composite cement. Because the grinding properties of clinker and auxiliary cementitious material are very different, the components of cement are caused. As the distribution of particles is not reasonable, the production of composite cement has many problems such as low early strength, long setting time and low content. Therefore, it is very important to study the effect of particle size distribution on the properties of cement based materials for the efficient utilization of the hydration activity of the auxiliary cementitious materials and to improve the performance of the composite cement. Two kinds of auxiliary cementitious materials, fly ash and Si-Mn slag, are used to separate fly ash and Si-Mn slag into fine, medium, coarse, medium, coarse (D5 0=5.0, 6, 15.63, 15.63, m, 35.01 m and D5 0=6.8 7 u m, 17.85 mu m, 56.4 micron). The experimental system studies the particle size of fly ash and slag, and the mechanical properties of cement mortar. Effects of energy and resistance to chemical erosion, and the effect of particle size distribution of fly ash and Si-Mn slag on hydration products of cement paste, hydration heat, microstructure and chemical erosion hydration products. The conclusions are as follows: (1) fine grained interval fly ash has a higher Ca O, SO3, alkaline oxide and burning loss, and different particle size fly ash particles With the increase of the particle size of the fly ash, the smooth spherical particles decrease with the increase of the particle size of the fly ash. With the increase of the particle size of Si-Mn ore, the content of Si O2, Al 2 O 3 and S O3 decreases, while Ca O, Mn O, Ba, and calcium aluminate diffraction peak intensity decreases with the increase of particle size; the thicker slag particles are more prismatic. (2) the strength of all ages of fly ash cement mortar decreased with the increase of fly ash content. The strength of Si-Mn slag cement in the later period of fine and medium size increased with the increase of slag content. With the decrease of fly ash and Si-Mn slag particle size, the age strength of cement mortar increased. (3) the particle size of fly ash and Si-Mn slag particles has a significant influence on the pore structure distribution of cement slurry. With the decrease of fly ash and Si-Mn slag particle size, the most pore size of cement slurry decreases. (4) the incorporation of fly ash inhibits the hydration heat rate and accumulative heat release of cement, and the hydration is about 12 h, and the cement slurry has an obvious acceleration period. The peak value of heat rate and fine-grained fly ash cement is obviously higher than that of the medium and coarse grained fly ash cement slurry. When the hydrated 120 h, the accumulation of heat of cement paste increases obviously with the decrease of the particle size of the fly ash, and the addition of.S i-M n slag particles obviously promotes the hydration rate of the early hydration of cement and the later stage of hydration, and the fine particles are fine. Si-Mn mineral cement has higher hydration rate. The accumulated heat of Portland cement is obviously higher than that of Si-Mn mineral cement in hydration 24h, and the accumulative exothermic curve of Si-Mn mineral cement is almost identical with each granularity. After the hydration of 24h, the accumulated heat of Si-Mn slag cement increases greatly and decreases with the particle size of Si-Mn mineral powder, and the accumulative heat release of cement increases. The greater the addition amplitude. (5) the strength of Ca (OH) 2 peak of different particle size fly ash and Si-Mn slag cement paste has no obvious difference (5) when hydrated, the strength of Ca (OH) 2 peak decreases with the decrease of fly ash and Si-Mn slag particle size. The fine slag and fly ash particles in the middle grain size range can effectively reduce the Ca (OH) 2 content. The finer the fly ash particles The more hydration products formed on the surface of the Si-Mn slag particles and the hydration of the fly ash particles on the surface of the fly ash particles are C-S (A L) -H gels of C a/S i=0.7 4, and the surface hydration of S i-M n slag particles is a kind of C granules 4. (6) the fly ash and slag cement mortar are eroded in sulfate and 60 respectively. The anticorrosion coefficient reached the maximum. The anticorrosion coefficient of cement age increased with the decrease of fly ash and S i-M n slag particle size, and fine particle size fly ash and Si-Mn particles could effectively improve the corrosion resistance of cement. The corrosion resistance coefficient of fly ash cement mortar increased with the prolongation of erosion age, and Si-M The corrosion resistance coefficient of N slag cement mortar occurred at the age of 28d. With the decrease of fly ash and Si-Mn slag particle size, the corrosion resistance coefficient of all ages increased obviously. (7) the diffraction peak of gypsum and Ettringite crystals formed by cement slurry was not obvious in the early stage of sulfate attack. When the particle size of fly ash and Si-Mn slag decreased, the particle size of fly ash and Si-Mn slag decreased. The intensity of ettringite and gypsum diffraction peak in the slurry is reduced. The main corrosion products of cement paste in simulated seawater are Ca4A L 2 O6 C L 2. 10 H2O (Friedel 's salt). When the erosion is 28 d, the particle size of fly ash and Si-Mn slag has no obvious effect on the Friedel' s salt of the eroded hydrated product. The decrease of the Friedel 's salt diffraction peak intensity is reduced.
【学位授予单位】：西南科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ172.1

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