水泥乳化沥青砂浆用干料组成与性能的研究

【作者】 杜火文；

【导师】 邓德华；

【作者基本信息】 中南大学 ， 土木工程， 2011， 硕士

【摘要】 水泥乳化沥青砂浆(简称CA砂浆)是板式无砟轨道结构中的关键材料之一,由水泥、乳化沥青、砂、添加剂和水等组成,经搅拌、灌注形成砂浆充填层。为提高施工效率,控制施工质量,通常先将水泥、砂和固态添加剂等材料经预混工艺制成水泥乳化沥青砂浆用干粉料(简称干料)。工程应用时,将干料、乳化沥青、水等材料搅拌成CA砂浆,即可灌注施工。干料的性能与质量对水泥乳化沥青砂浆充填层和板式无砟轨道结构的性能、质量与耐久性有重要影响。目前,国外内有关这种干料性能的研究报道较少,因此,对干料开展深入的研究是非常必要的。本文主要研究了砂的颗粒级配、细度模数和最大粒径对新拌CA砂浆性能的影响；通过研究膨胀组分(铝粉与U型膨胀剂)的掺量和不同养护条件下干料与CA砂浆的膨胀特性,揭示了干料与CA砂浆体积膨胀特性与发展规律；探索了干料生产的投料工艺、分散工艺和最佳搅拌时间的确定方法；总结了干料质量控制与检测方法；通过模拟试验,得出了干料储存过程中的失效机理。得到的主要结论如下：(1)砂的细度模数是影响干料与CA砂浆流动性能的主要因素；细度模数相同时,砂的颗粒级配对干料与CA砂浆流动性无明显影响；细度模数与最大粒径是影响CA砂浆匀质性的主要因素。(2)CA砂浆的早期膨胀率随铝粉掺量的增加而增大,随铝粉粒径的减小而增大；养护温度越高,CA砂浆的早期膨胀越迅速,膨胀率越大；CA砂浆后期膨胀率随U型膨胀剂掺量增加而增大；养护湿度对CA砂浆后期膨胀率的影响较小。(3)生产干料的最佳投料顺序为：水泥、膨胀剂、复合添加剂、砂；采用预分散技术能大大提高铝粉在干料中的分散均匀性。(4)随着干料储存龄期的增长,其配制的CA砂浆的膨胀特性与匀质性均会发生改变,干料储存过程中失效的机理是：干料中的水泥熟料矿物成分、铝粉与空气中的水分发生反应而部分失效,干料组成改变而影响其性能。更多还原

【Abstract】 Cement and emulsified asphalt mortar (CA mortar), which consists of cement, emulsified asphalt, sand, water and other admixtures, is one of the key materials of the slab ballastless track structure. In order to improve the efficiency of construction and the quality of CA mortar, cement, sand and other solid admixtures are mixed to the mixtures for CA mortar. At the construction site, the mixtures are mixed with the emulsified asphalt and water, forming the fresh CA motar for the CA motar layer in the slab ballastless track structure. Thus, the performance and quality of the mixtures have a significant effect on the performance, quality and durability of CA mortar layer. Now, the studies on the mixtures are little.In this article, the effects of the size distribution, fineness modulus and maximum size of sand particle in the mixtures on the fresh CA mortar, and the expansive components (aluminium powder and U-shaped expansive agent) and curing conditions on the expansion properties of CA mortar were investigated. Also, the production process and its technological parameter of the mixtures were determined; the effective measure to control the quality of the mixtures was discussed. Finally, the deterioration mechanism of the mixtures during storage was analysed.The main conclusions are summarized as follows:(1) The fineness modulus of sand particles in the mixtures is the main factor influencing the flowability of the fresh CA mortars, but when sand fineness modulus is the same, the size distribution of sand particles has no obvious effect on the flowability of fresh C A mortars. The fineness modulus and maximum size of sand particles are the main reasons influencing the uniformity of CA mortar.(2) The early-age expansion ratio of CA mortar is increased with an increase in the content of aluminium power and a decrease in particle size of aluminium power. The higher curing temperature is, the rapider early-age expansion of CA mortar becomes, and the higher expansion ratio is. Later-age expansion ratio is increased with an increase in the content of U-shaped expansive agent. The later-age expansion ratio of CA motar is not susceptible to the curing humidity.(3) It is the best process for manufacturing the mixtures for CA motar that cement, expansion agent, other admixtures and sand are added in turn to be mixed in the mixer. The pre-dispersion technology used can significantly raise the dispersion of aluminium powder in the mixtures.(4) As the storage age of the mixtures is increased, the expansion ratio and uniformity of CA mortar will be changed due to the deterioration of the mixtures. The deterioration mechanism of the mixtures is that the reaction between mineral components of cement and aluminium powder and the moisture in the air can be occurred during storage.更多还原