废旧轮胎橡胶改性粉土的工程特性研究

发布时间：2018-01-19 13:25

本文关键词： 废旧轮胎胶粉胶条粉土固化稳定击实特性强度冻融循环　出处：《东南大学》2017年硕士论文　论文类型：学位论文

【摘要】：废旧轮胎被称为"黑色污染",是交通运输工程领域的一种废弃物;而粉土路基的处理是我国交通工程建设中亟待解决的技术难题。若能将废旧轮胎的再利用与粉土改良技术相结合,对减少污染、提高粉土路基改性技术具有重要意义。本文结合现有研究成果,选取江苏省徐州地区粉土作为加固对象,采用多种废旧轮胎橡胶颗粒为添加剂,水泥为改性剂,通过室内试验与理论分析,对废旧轮胎橡胶改性土的工程特性和改性机理进行了研究。主要研究成果如下:(1)通过击实试验表明,添加废旧轮胎橡胶后,改性土的最大干密度显著降低,因此废旧轮胎改性土有非常好的轻质性,同时改性土击实曲线相较粉土均向左移动;同掺量下胶粉对最大干密度的降低作用更明显,而胶条对最大含水率的影响更大。改性土击实曲线左移,原因在于橡胶的加入增加了土颗粒的击实功。(2)无侧限抗压试验结果表明,废旧轮胎橡胶的掺入会使得改性土强度有所降低,且轮胎橡胶会对水泥的水化有一定的抑制作用;但在胶条掺量为5%时,养护后试样强度能达到水泥土的强度甚至高于水泥土,该配比下改性土强度最佳。(3)直剪试验结果表明,胶粉和胶条的加入可以提高固化土的抗剪强度,其c和φ同时增大。(4)通过冻融循环试验发现,废旧轮胎胶条改性土经历冻融循环后,强度有所下降,在第六级循环达到最低值。改性土试样受第一级冻融循环影响较大,含水率和干密度波动变化达到峰值。机理主要是,胶条掺入使得改性土孔隙率增大,减小了水分冻胀造成的影响;且胶条具有弹性作用,会承担部分水分胀缩带来影响。因此胶条改性土有良好的的抗冻融性能。
[Abstract]:Waste tires are called "black pollution", which is a kind of waste in the field of transportation engineering. The treatment of silt subgrade is a technical problem to be solved urgently in traffic engineering construction in China. If the reuse of waste tires can be combined with silt improvement technology, it will reduce pollution. It is of great significance to improve the modification technology of silt roadbed. Combined with the existing research results, the silt in Xuzhou area of Jiangsu Province is selected as the reinforcement object, and a variety of waste tire rubber particles are used as additives and cement as modifier. Through laboratory test and theoretical analysis, the engineering characteristics and modification mechanism of waste tire rubber modified soil are studied. The main research results are as follows: 1) through compaction test, it is shown that after adding waste tire rubber. The maximum dry density of the modified soil decreased significantly, so the waste tire modified soil had a very good light quality, and the compaction curve of the modified soil moved to the left compared with the silt. The effect of rubber powder on the decrease of maximum dry density is more obvious than that of rubber strip on the maximum moisture content. The compaction curve of modified soil is shifted to the left. The reason is that the addition of rubber increases the compaction power of soil particles. 2) the results of unconfined compression test show that the strength of the modified soil can be reduced by the addition of waste tire rubber. The tire rubber can inhibit the hydration of cement to a certain extent. However, when the content of rubber strip is 5, the strength of the sample after curing can reach the strength of cement soil even higher than that of cement soil, and the strength of modified soil under this ratio is the best. The addition of rubber powder and rubber strip can improve the shear strength of the cured soil, and its c and 蠁 increase at the same time. (4) through the freeze-thaw cycle test, it is found that the strength of the waste tire rubber strip modified soil decreases after the freeze-thaw cycle. The sample of modified soil was greatly affected by the first stage freeze-thaw cycle, and the fluctuation of water content and dry density reached the peak. The main mechanism was that the porosity of modified soil was increased by the addition of rubber strip. The effect of water frost heaving is reduced; And the rubber strip has elastic effect, it will bear part of the effect of water swelling and shrinkage, so the rubber strip modified soil has good freeze-thaw resistance.
【学位授予单位】：东南大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U416.1

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