干湿与冻融耦合作用下稻壳灰水泥土疲劳特性  

Fatigue characteristics of rice husk ash cement-soil under coupled action of dry-wet and freeze-thaw

作　　者：张城芋 陈四利 江双双 段新超 ZHANG Chengyu;CHEN Sili;JIANG Shuangshuang;DUAN Xinchao(College of Architecture and Civil Engineering,Shenyang University of Technology,Shenyang,Liaoning 110870,China)

机构地区：[1]沈阳工业大学建筑与土木工程学院,辽宁沈阳110870

出　　处：《排灌机械工程学报》2023年第6期562-567,575,共7页Journal of Drainage and Irrigation Machinery Engineering

基　　金：国家自然科学基金资助项目(51279109,51608332);辽宁省自然科学基金资助项目(2019-MS-242)。

摘　　要：针对水泥土路面基层在反复荷载作用下疲劳性能的问题,利用全试验方法研究了稻壳灰水泥土疲劳寿命随不同稻壳灰掺量、干湿循环次数、冻融循环以及干湿循环与冻融循环耦合作用下的变化规律,并借助扫描电镜对稻壳灰水泥土内部微观结构变化及机理进行了分析.研究结果表明:稻壳灰水泥土的疲劳寿命随稻壳灰掺量及干湿循环次数的增加均呈现先变长后变短的趋势,干湿循环次数为7次时,疲劳特性最优,稻壳灰最优掺量为12%;而稻壳灰水泥土的疲劳寿命随冻融循环次数增加而逐渐变短.在干湿与冻融环境耦合作用下,稻壳灰水泥土疲劳寿命随作用次数的增加而逐渐变短.微观分析表明,稻壳灰中大量活性物质SiO_(2)与水泥水化反应生成的Ca(OH)2发生二次水化反应,生成更多胶凝物质C-S-H,其对盐溶液中SO_(4)^(2-)的侵蚀有抑制作用.研究结果为稻壳灰水泥土在实际工程中的应用提供了坚实的理论基础.In view of the fatigue performance of the pavement base layer under repeated loading,the full test method was used to study the variation of the fatigue life of rice husk ash cement-soil with different rice husk ash content,number of dry wet cycles,freeze-thaw cycle,and the coupling of dry-wet cycle and freeze-thaw cycle.The changes and mechanism of the internal microstructure of rice husk ask cement-soil were analyzed by electron microscopy scanning test.The research results indicate that the fatigue life of rice husk ash cement-soil increases with the increase of the dosage and the number of dry-wet cycles shows a trend of rising first and then falling.When the number of dry-wet cycles is 7,the fatigue characteristics are optimal,and the optimal dosage of rice husk ash is 12%.The fatigue life of rice husk cement-soil gradually decreases with the increase of freeze-thaw cycles.Under the coupling effect of dry-wet and freeze-thaw environments,the fatigue life of rice husk ash cement-soil gradually decreases with the increase of the number of action.Microscopic analysis indicates that a large amount of active substance SiO_(2) in rice husk ash that is formed by the reaction of cement hydration Ca(OH)2 undergoes secondary hydration reaction,generating more cementitious species C-S-H,which can inhibit the erosion of SO_(4)^(2-) in saline solution.This paper provides a solid theoretical basis for the application of rice husk ash cement-soil in practical engineering.

关 键 词：环境耦合作用 稻壳灰 水泥土 疲劳特性 微观结构 

分 类 号：TU43[建筑科学—岩土工程]