大掺量高性能矿渣微粉对水泥基材料性能影响的研究

发布时间：2018-03-20 08:22

本文选题：矿粉　切入点：水泥　出处：《武汉理工大学》2015年硕士论文　论文类型：学位论文

【摘要】：目前矿渣微粉在水泥基材料中已得到广泛应用,但其等量替代水泥的掺量一般在30wt%以内。提高矿渣微粉在水泥基材料中的掺量,了解高掺量矿渣微粉水泥基材料的基本性能,尤其是长期力学性能与耐久性,对于提高矿渣利用率、减少水泥消耗量而保护生态环境具有重要意义。本文以武钢的高性能矿渣微粉(以下简称为矿粉)、42.5普通硅酸盐水泥为对象,研究了不同掺量(10wt%-90wt%,等量取代水泥)的矿粉对水泥基本性能影响规律;在此基础上,采用不同掺量(30 wt%、40 wt%、50 wt%和60 wt%)的矿粉制备了C40大流态混凝土,研究了其工作性能、长期力学性能与耐久性,取得的主要结论如下:(1)以水泥为基准样,随着矿粉掺量在10wt%-90wt%范围内逐步递增时,水泥标准稠度需水量逐渐降低,最大降幅为14.3%;凝结时间则逐步延长,最大延长62.5%;砂浆流动度逐步增大,最大增幅为10.4%。当矿粉掺量分别在40wt%以内与50wt%-70wt%时,水泥胶砂的28d强度分别能满足42.5与32.5普通硅酸盐水泥的强度要求。(2)以不掺矿粉的C40大流态混凝土为对比,随着矿粉掺量在30wt%-60wt%范围内递增时,混凝土的坍落度增大(最大增幅23.0%),坍落度经时损失降低(最大降幅(1h)11.2%);抗压强度增长率在28d龄期内是降低的,而在60d龄期后则逐步增大,其中在矿粉掺量40wt%时,90d与180d龄期的强度已超过基准样;各龄期的抗折强度则呈递增的趋势,其中矿粉掺量40wt%的增幅最大。(3)随着矿粉掺量的增大,混凝土的干燥收缩率增大,尤其是在大掺量、早龄期条件下;混凝土的电通量逐步降低,表明其抗氯离子渗透性能随矿粉掺量的增加而增强;混凝土的冻融循环质量损失增大、相对弹性模量降低,表明混凝土的抗冻性随矿粉掺量的增加而降低。综上所述,矿粉在水泥基材料中的掺量可以提高到40wt%,水泥与混凝土的各项性能整体上较优,并可以通过不断调整矿粉在水泥中的掺量满足不同强度的水泥混凝土需求。
[Abstract]:At present, slag micro-powder has been widely used in cement based materials, but its equal amount of substitution cement is generally less than 30wt%. The basic properties of cement based materials with high content of slag micro-powder can be understood by increasing the content of slag micro-powder in cement base materials. In particular, the long-term mechanical properties and durability can improve the utilization ratio of slag. It is of great significance to reduce cement consumption and protect ecological environment. On the basis of the study on the effect of mineral powder with different dosage of 10wt- 90 wtand) on the basic properties of the cement, C40 large-flow concrete was prepared by using the mineral powder with different dosage of 30 wttand 40 wtt% and 60wtttmeter respectively, and its working properties were studied. For long-term mechanical properties and durability, the main conclusions obtained are as follows: (1) taking cement as a reference sample, with the increase of mineral powder content in the range of 10 wt-90 wt%, the water requirement of cement standard consistency decreases gradually, the maximum decrease is 14.3wt%, and the setting time is gradually prolonged. The maximum prolongation is 62.5 and the flow degree of the mortar increases gradually, with the maximum increase of 10.40.When the mineral powder content is within 40wt% and 50wt% and 70wt% respectively, The 28d strength of cement sand can meet the strength requirements of 42.5 and 32.5 ordinary Portland cement respectively. The slump of concrete is increased (the maximum increase is 23.0%, the slump loss decreases (the biggest drop is 1 h), the compressive strength growth rate decreases during 28 d, but increases gradually after 60 d age, the increase of compressive strength increases gradually after the age of 60 days, and the increase of compressive strength increases gradually after the age of 60 days, but the increase of compressive strength increases gradually after the age of 60 days. The strength of 90 days and 180 days of age is higher than that of the standard sample, and the flexural strength of each age shows an increasing trend, in which the increase of 40 wt% of mineral powder is the biggest. 3) with the increase of mineral powder content, the drying shrinkage rate of concrete increases, and the dry shrinkage of concrete increases with the increase of mineral powder content. Especially under the condition of large dosage and early age, the electric flux of concrete decreases gradually, which indicates that the resistance to chloride ion permeability increases with the increase of mineral powder content, and the mass loss of freeze-thaw cycle increases and the relative elastic modulus decreases. The results show that the frost resistance of concrete decreases with the increase of mineral powder content. In conclusion, the content of mineral powder in cement based materials can be increased to 40 wt.The properties of cement and concrete are better as a whole. The cement concrete needs of different strength can be satisfied by continuously adjusting the amount of mineral powder in cement.
【学位授予单位】：武汉理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU528

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