冻融循环作用下改良灰土力学特性与孔隙特征试验研究  

Experimental study on mechanical properties and pore characteristics of the modified lime mortars under freee-thaw cycles

作　　者：刘春龙 刘奉银[2] 黄素娟[1] 付争 王锐 王松鹤[2] LIU Chunlong;LIU Fengyin;HUANG Sujuan;FU Zheng;WANG Rui;WANG Songhe(Center of Highway and Transportation Management,Pingyang County Traffic and Transportation Bureau,Pingyang 325400,Zhejiang,China;Institute of Geotechnical Engineering,Xi’an University of Technology,Xi’an 710048,China;Xi’an TBEA Electric Power Design Institute,Xi’an 710119,China;School of Civil Engineering,Northeast Forestry University,Harbin 150040,China)

机构地区：[1]平阳县交通运输局公路与运输管理中心,浙江平阳325400 [2]西安理工大学岩土工程研究所,陕西西安710048 [3]西安特变电工电力设计院,陕西西安710119 [4]东北林业大学土木工程学院,黑龙江哈尔滨150040

出　　处：《冰川冻土》2022年第6期1833-1841,共9页Journal of Glaciology and Geocryology

基　　金：国家自然科学基金项目(12072260;51679198)资助。

摘　　要：石灰土作为路基填料代替宕渣是一种较为经济的方案,但灰土初始强度低、硬化速率慢、碳化时间长,不利于快速施工,需要进行改良研究。利用偏高岭土与石灰发生火山灰反应的原理改良灰土,通过单轴压缩试验和三轴压缩试验,分析改良灰土冻融循环条件下力学参数变化规律,利用图像处理技术提取改良灰土图像表面孔隙,建立孔隙率与强度的关系,并通过研究龄期、石灰含量和含水率变化规律,分析偏高岭土改良灰土的机制。结果表明:偏高岭土能够有效提高灰土材料反应速率,改善灰土力学特性;偏高岭土在一定程度上能够恢复冻融循环导致的灰土力学性能损失,降低冰晶体产生的孔隙;灰土强度达到最优后,其强度随着石灰的增加而降低,而经偏高岭土改良后其强度将继续增加;火山灰反应比灰土碳化过程消耗更多的水分,有效提高了灰土的抗冻性能。It is an economical solution to replace slag using lime mortars as subgrade filler. However, lime mortars has low initial strength, slow hardening rate, and long carbonization time, which is not conducive to rapid construction. In this paper, the pozzolanic reaction between metakaolin and lime is used to improve lime mortars. Through uniaxial compression testing and triaxial compression testing, the mechanical parameters of improved lime mortars under freeze-thaw cycles is analyzed. The surface porosity of improved lime mortars image is extracted by image processing technology, and the relationship between porosity and strength is established.The mechanism of improved lime mortars in metakaolin is analyzed by studying the age, lime contents and moisture contents. The results show that: metakaolin can effectively increase the reaction rate and mechanical properties of lime mortars;metakaolin can restore the loss of mechanical properties of lime mortars caused by freezethaw cycle to a certain extent, and reduce the pores caused by ice crystals;after reaching the optimum strength, the strength of lime mortars will decrease with the increase of lime, while it will continue to increase after being improved by metakaolin;the pozzolanic reaction consumes more water than the carbonation process of lime mortars, and effectively improves the frost resistance of lime mortars.

关 键 词：冻融循环 强度 孔隙率 改良灰土 图像处理 

分 类 号：TU44[建筑科学—岩土工程]