【作者】 张勇；

【导师】 赵庆新； 李化建；

【作者基本信息】 燕山大学 ， 建筑与土木工程（专业学位）， 2016， 硕士

【摘要】 自密实混凝土作为CRTSⅢ型板式无砟轨道结构充填层的填充材料,其稳定性的优劣对轨道系统的正常使用具有重要影响,因此,配制出稳定性良好的充填层自密实混凝土具有十分显著的社会、经济效益,对推动我国高速铁路发展具有重要意义。本文以CRTSⅢ型板式无砟轨道结构充填层自密实混凝土的静态稳定性为研究对象,介绍了混凝土的静态离析机理,综述并筛选了自密实混凝土静态稳定性评价方法,确定了试验原材料及方案,并在理论分析基础上对柱状法进行了改进,提出砂浆离析百分数来表征自密实混凝土静态稳定性,同时研究了自密实混凝土配比参数等对其静态稳定性的影响,建立了充填层自密实混凝土基本工作性能与其静态稳定性间的关系。研究发现,自密实混凝土水胶比、减水剂用量和粗骨料最大粒径增加在提高其基本工作性能的同时会降低其静态稳定性,而引气剂含量、粗骨料体积分数的增加则存在相反作用;骨料集配对自密实混凝土基本工作性能和静态稳定性的影响会以其最佳集配为基础呈对称趋势变化;各影响因素对自密实混凝土静态稳定性影响程度按变异系数大小依次为水胶比、骨料体积分数、减水剂用量、含气量、骨料级配和骨料最大粒径;同时,自密实混凝土的竖向膨胀率(24 h)与其静态稳定性间不存在明显相关性。贯入试验、GTM筛稳定性试验和柱状法试验三种试验方法对自密实混凝土静态稳定性敏感程度依次提高;以柱状法试验和筛分试验结果为参考,当自密实混凝土静态稳定性良好时,贯入试验评价标准上限值可适当提高到7 mm;在对柱状法简化过程中,当砂浆离析百分数不大于12.8%时,自密实混凝土静态稳定性良好,且该指标与静态离析百分数线性相关;自密实混凝土流动时间的延长或扩展度的降低均有利于静态稳定性的提高;同时,自密实混凝土的流动时间Tfin、T600和T500对其静态稳定性敏感程度依次递减;另外,当自密实混凝土基本工作性能至少满足5.3 s≤T500≤20.0 s,12.1 s≤T600≤46.3 s,35.7 s≤Tfin≤63.5 s和550 mm≤坍落扩展度≤715mm中的三项时,可判定其静态稳定性良好。更多还原

【Abstract】 As the filling material of the specific filling layer of the CRTSⅢ type system, the stability of SCC has big influences on the normal use of the track system, so a stable SCC has a significant meaning for the benefit of the society and economy, and which can also benefit the development of the high speed railway.Based on the static stability of filling layer SCC of CRTSⅢ slab ballastless track system, a simple introduction of the static segregation mechanism of SCC was made, the raw materials and the experimental method were confirmed, and the penetration test, the column test and the sieve segregation test were selected as the reference test method. And based on the test, the column test was improved, the effect of the parameters of the mix design and the workability and the vertical deformation of SCC on the static stability were studyed, meanwhile, a connection was also made between the workability and the static stability of SCC.Through the research, it was found that, increasing the W/B, dosage of SP and diameter of the coarse aggregate could improve the basic workability but decrease the static stability of SCC, but the expansion agent and the coarse aggregate volume fraction have the opposite effect. the grading curve of coarse aggregate is optimal, the workability and static stability of SCC will changed symmetric around it. Based on the difference of the coefficient of variation, the parameters which have influence to the static stability of SCC could ranking as W/B>Volume frication of aggregate>Dosage of SP>Air content>Grading of aggregate>Maximum size of aggregate; And the vertical deformation rate of SCC of a day has little connection with the static stability of SCC.The test result of the column test is sensitive to the GTM sieving test and the penetration test; Taking the test results of the column test and the GTM sieving test as reference, when the static stability of SCC is good, the upper value of the penetration depth could be adjusted to 7 mm; When the static segregation percent(mortar) is less than 12.8 %, SCC has a good static stability, and the mortar segregation percent and the static segregation percent are related linearly; Meanwhile, a longer flow time or a shorter slump flow mean a better static stability; and it’s a decreasing trend of the sensitivity of the flow time to the static stability of SCC from Tfin to T500; Besides SCC is considered to have a good static stability when at least three of the basic workabilities are satisfied, T500 between and including 5.3 s and 20.0 s, T600 between and including 12.1 s and 46.4 s, Tfin between and including 35.7 s and 63.7 s, the slump flow between and including 550 mm and 715 mm.更多还原