超细石灰石粉在活性粉末混凝土中的应用研究

发布时间：2018-01-04 15:36

本文关键词：超细石灰石粉在活性粉末混凝土中的应用研究　出处：《重庆大学》2016年硕士论文　论文类型：学位论文

【摘要】：RPC是一种超高性能混凝土材料,应具有超高的力学性能,优异的耐久性能和韧性,良好的经济性和环境友好性。但由于RPC中水泥用量过大,既不经济,同时对强度的贡献率也不高。大量的未水化水泥颗粒存在于硬化结构中对资源是浪费,对体积稳定性也是隐患。因此,寻找较为廉价的矿物细粉来替代RPC组分,形成成本低廉、工艺简单的生产线,仍然是今后需要加强和改善的方向。石灰石粉由于具有较低的表面能,分散性良好,石灰石粉的加入大大降低了活性粉末混凝土的黏性,改善传统高水泥用量的RPC的物理性能。石灰石粉在大掺量矿物细粉RPC中的掺加,有效解决了由于RPC黏度太大导致的制备工艺要求高的技术难题。为大掺量矿物细粉RPC的大规模生产提供了一种降低拌合物黏度的技术选择,这是其他掺合料不能具有的特性。同时RPC具有极低的水胶比,对胶凝材料中高活性组分的数量需求是有限的,这为石灰石粉的应用提供了技术可行性。本课题通过试验优化了活性粉末混凝土的配合比,研究超细石灰石粉取代胶凝材料(水泥、硅灰)及石英粉对RPC性能的影响。研究了超细石灰石粉RPC的微观结构及界面性能,分析了超细石灰石粉RPC孔结构与强度的关系。试验结果表明:通过对胶凝材料组成的优化得出最优配合比为,水泥:硅灰:石英砂:石英粉=1:0.25:1.1:0.37。超细石灰石粉的掺入可以有效的改善拌合物的工作性能。其中当采用400目石灰石粉完全取代石英粉(取代率100%),1250目石灰石粉取代胶凝材料(水泥、硅灰)15%的情况下,配制出标准养护条件下,28天抗折强度20.1MPa,抗压强度107.7MPa,90℃热水养护条件下,28天抗折强度27.2MPa,抗压强度136MPa的RPC材料。超细石灰石粉的掺入不仅大大降低了生产RPC的成本,提高了经济效益,而且对于环境也起到了保护作用。其中每生产1m3的超细石灰石粉RPC将降低成本约146元。在掺入超细石灰石粉后,RPC内部水化物分布更加均匀,水化物更加致密,超细石灰石粉分散在RPC内部,加速了水泥水化反应的进程,并且为水化产生的C-S-H凝胶提供了充裕的空间,改善了水化产物分布的均匀性,有效的改善水泥石与石英砂界面区的性能,使水化凝胶产物紧密粘接,且“融为一体”,凝胶体非常密实,分布均匀。超细石灰石粉淡化了骨料与水泥浆体的界面过渡区,提高了水泥石界面区密实度和结构致密性,同时,超细石灰石粉的掺入改善了RPC内部孔结构,细化了孔径,使得RPC结构更加密实。
[Abstract]:RPC is a kind of ultra high performance concrete materials, with super high mechanical property, excellent durability and toughness, economy and environment friendly. But RPC due to excessive use of cement is not economic, but also the intensity contribution rate is not high. A large number of unhydrated cement the particles in the structure of hardening is a waste of resources, the volume stability is hidden. Therefore, looking for mineral powder cheaper to replace the RPC component, the formation of low cost, simple production line, is still the need to strengthen and improve the direction in the future. Because the limestone powder has low surface energy and dispersion well, adding limestone powder can greatly reduce the viscosity of reactive powder concrete, improve the physical performance of traditional high dosage of cement RPC. Limestone powder in high volume fine mineral powder RPC in addition, effectively solves the RPC viscosity is too large to The preparation process requires high technical problems. Provides a lower mixture viscosity the technology of choice for mass production of high volume fine mineral powder RPC, which is characteristic of other admixtures cannot have. RPC also has a very low water binder ratio, is limited to the high number of active components the demand of cementitious materials, which provides the technical feasibility for the application of lime powder. The optimized matching of reactive powder concrete, cementitious material instead of super fine limestone powder (cement, silica fume) and quartz powder on the performance of RPC. The microstructure and interfacial properties of the ultra fine limestone powder RPC RPC, analyzes the relationship between the pore structure and strength of super fine limestone powder. The experimental results showed that by optimizing the composition of cementitious materials to obtain the optimal mix ratio, cement, silica fume: quartz sand: =1:0.25:1.1:0.37. superfine quartz powder lime powder The incorporation of the work to improve the performance of the mixture effectively. When using 400 mesh limestone completely replace quartz powder (1250 mesh, 100% substitution rate) to replace the limestone cementitious materials (cement, silica fume) 15%, prepared under standard curing conditions, the flexural strength of 28 days 20.1MPa, the compressive strength of 107.7MPa 90, hot water curing condition, the flexural strength of 28 days 27.2MPa, 136MPa compressive strength of RPC material. The incorporation of super fine limestone powder not only greatly reduce the production cost of RPC, improve economic efficiency, but also for the environment also plays a protective role. Each production of 1m3 super fine limestone powder will reduce the cost of RPC about 146 yuan. The incorporation of super fine limestone powder, RPC hydrate distribution is more uniform, hydrate is more compact, ultra fine limestone powder dispersed in RPC, accelerates the hydration of cement process, and C-S-H gel produced by hydration Provide ample space, improve the uniformity of the distribution of hydration products, effectively improve the performance of cement and quartz sand interface, the hydration product of gel bonded tightly, and the "integrated", gel very dense, uniform distribution. Ultra fine limestone powder dilute the interfacial transition zone of aggregate and cement paste and improve the dense cement paste interfacial zone and dense structure, at the same time, ultra fine limestone powder. Improve the pore structure of RPC, refinement of the aperture, the RPC structure is more compact.

【学位授予单位】：重庆大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TU528

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