后张法预应力梁孔道压浆材料的研制

发布时间：2018-02-05 21:18

本文关键词： 后张法预应力梁压浆剂流变性能力学性能适应性　出处：《中南大学》2014年硕士论文　论文类型：学位论文

【摘要】：孔道压浆是后张法预应力混凝土梁中最重要的环节之一,作为保护预应力筋的最后一道防线,其质量好坏对于后张预应力混凝土结构的安全性和耐久性具有极其重要的意义。随着《公路桥涵施工技术规范》(JTG/TF50-2011)的颁布实施,对于后张预应力孔道压浆材料的性能提出了更高的要求。工地自制的压浆材料往往不能满足规范要求,而市场上仅有的几种压浆材料价格较高。本文依托佛山质检站后张预应力梁高性能孔道压浆材料研究项目,研制了一种满足规范要求的低成本高性能孔道压浆材料。以经济和实用为基本原则,选取常用的水泥、掺合料、外加剂等原材料,首先对减水剂、粉煤灰和硅灰的掺量进行粗选,确定其正交试验的水平。然后以水胶比、减水剂掺量、粉煤灰掺量和硅灰掺量为因素进行正交试验,优化原材料的配伍。再以正交试验结果为基础优选缓凝剂、消泡剂和微膨胀剂等组分优化压浆材料的配比。研究了矿物掺合料、水胶比和搅拌工艺对压浆材料的流变性能和力学性能的影响规律并从理论上分析了压浆材料在马氏漏斗中的流动过程,在宏观性能测试的基础上对硬化浆体进行了XRD、SEM试验分析,最后研究了压浆剂与水泥的适应性。主要研究成果如下： 1、粉煤灰和硅灰双掺不仅能够提高压浆材料的流动性能,而且对于降低泌水率、提高浆体的力学性能具有非常好的效果；微膨胀剂能够有效地改善压浆材料的膨胀性能,但会降低流动性能；优化配制的满足JTG/TF50-2011规范要求的高性能孔道压浆剂(以胶凝材料总量计)：聚羧酸减水剂掺量0.25%、粉煤灰掺量10%、硅灰掺量3%、微膨胀剂掺量6%、葡萄糖酸钠掺量0.05%、消泡剂掺量0.05%。 2、搅拌工艺对于压浆材料的流动度、泌水率、膨胀率和力学性能均具有一定的影响,搅拌的速度5000r/min、搅拌4min能够得到最佳综合性能的压浆材料；水胶比对压浆材料的影响显著,综合规范要求和试验结果,水胶比宜采用0.28；马氏漏斗可作为一种粘度测试仪且压浆材料在流动度低于20s时流变性能接近牛顿流体。 3、所研制的压浆剂与水泥具有较好的适应性；通过水泥的标准稠度用水量、细度、铝酸盐矿物组成和早期强度可以判断压浆材料的流动度：标准稠度用水量越高、早期强度越高、铝酸盐含量越大的水泥品种配制的压浆材料流动性越差。
[Abstract]:Channel grouting is one of the most important links in post-#china_person0# prestressed concrete beam, which is the last line of defense to protect prestressed tendons. Its quality is of great significance for the safety and durability of post-tensioned prestressed concrete structures. With the promulgation and implementation of the Technical Specification for Highway Bridge and culvert Construction JTG / TF50-2011). The performance of post-tensioned prestressing channel grouting material is higher. The self-made grouting material can not meet the requirements of specifications. However, the price of only a few grouting materials in the market is high. This paper relies on the research project of post-tensioned prestressed beam high performance grouting material of post-tensioned prestressed beam in Foshan quality Inspection Station. A low-cost and high-performance porous slurry material has been developed to meet the requirements of specifications. Based on the principle of economy and practicality, the raw materials such as cement, admixture and admixture are selected. Firstly, the amount of water reducer, fly ash and silica fume is selected. Determine the level of orthogonal test. Then take the water / binder ratio, water reducer, fly ash and silica fume as the factors to optimize the compatibility of raw materials. Then based on the results of orthogonal test to select the retarder. The composition of defoamer and micro-expansion agent was optimized and the mineral admixture was studied. The effects of water / binder ratio and stirring process on the rheological and mechanical properties of grouting materials were studied and the flow process of grouting materials in Markov funnel was analyzed theoretically. On the basis of macroscopical performance test, the XRDX SEM test of hardened paste was carried out, and the adaptability of the grouting agent to cement was studied. The main research results are as follows: 1. The addition of fly ash and silica fume can not only improve the fluidity of the slurry, but also reduce the bleeding rate and improve the mechanical properties of the slurry. The micro-expansion agent can effectively improve the swelling performance of the slurry material, but it can reduce the fluidity of the slurry material. Optimized preparation of high performance pore grouting agent to meet the requirements of JTG/TF50-2011 specification (in terms of the total amount of cementitious material: polycarboxylic acid water reducer 0.25, fly ash 10%). The amount of silica fume is 3, the amount of micro-expansion agent is 6, the amount of sodium gluconate is 0.05, the amount of defoamer is 0.05. 2, the stirring process has certain influence on the flow degree, bleeding rate, expansion rate and mechanical properties of the slurry material, and the stirring speed is 5000r / min. After stirring for 4 min, the best material with comprehensive properties can be obtained. The water-binder ratio has a significant effect on the grouting material. The water-binder ratio should be 0.28 according to the requirements of the specifications and the test results. The Markovian funnel can be used as a viscosity tester and the rheological property of the slurry material is close to Newtonian fluid when the fluidity is lower than 20 s. 3. The compacting agent has good adaptability to cement. According to the standard consistency water consumption fineness aluminate mineral composition and early strength we can judge the fluidity of the slurry material: the higher the water consumption of the standard consistency the higher the early strength. The higher the aluminate content is, the worse the fluidity of the grouting material is.
【学位授予单位】：中南大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U445.57

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