摘要
为探求盐渍土等化学环境下混凝土力学性能变化规律及细观机制,以西北地区混凝土常用粗骨料灰岩为研究对象,开展灰岩浸泡在pH值为2,5,7,9,12的CaCl_(2)溶液和Na_(2)SO_(4)溶液中的化学腐蚀试验。利用纳米压痕力学试验和扫描电镜观测技术,开展化学溶液侵蚀下的灰岩细观力学试验研究。研究结果表明:经过化学腐蚀的灰岩试样,其弹性模量及硬度均有不同程度的降低,表现出一定的时效性。对灰岩试样的腐蚀性表现为CaCl_(2)溶液>Na_(2)SO_(4)溶液;同时,对灰岩试样的影响程度为酸性环境>碱性环境。溶液中pH值及离子浓度的变化与试样的损伤密切相关,表现为酸碱度越高及离子浓度越大,试样的力学参数降低越明显。灰岩对溶液的p H值最为敏感,对灰岩化学腐蚀起主要作用的是溶液中的H^(+)和OH^(-)。最后,引入以弹性模量定义的新损伤变量描述化学损伤后灰岩的力学性质劣化程度,并分析灰岩的损伤变量与其他力学参数之间的关系,研究发现损伤变量与硬度密切相关,硬度越小,力学参数降低程度越大。
In order to explore the change law and meso-mechanism of the mechanical properties of concrete in chemical environments such as saline soil.Limestone,which is commonly used as a coarse aggregate for concrete in Northwestern China,is used as the research object.The chemical corrosion tests of limestone immersed in CaCl_(2)solution and Na_(2)SO_(4)solution with pH=2,5,7,9,12 were carried out.Nanoindentation mechanics test and scanning electron microscope observation technology are used to carry out the micromechanical test research of limestone under chemical solution erosion.The results of the study indicate:After chemical corrosion,the elastic modulus and hardness of the limestone samples are reduced to varying degrees.The limestone sample shows a certain timeliness.The corrosiveness of limestone samples is CaCl_(2)solution>Na_(2)SO_(4)solution.At the same time,the degree of influence on the limestone sample is acidic environment>alkaline environment.The changes of pH and ion concentration in the solution are closely related to the damage of the sample.It shows that the higher the p H and the higher the ion concentration,the lower the mechanical parameters of the sample.Limestone is most sensitive to the p H of the solution.The main effects on the chemical corrosion of limestone are H^(+)and OH^(-)in the solution.Finally,a new damage variable defined by elastic modulus is introduced to describe the degradation degree of the mechanical properties of limestone after chemical damage At the same time,the relationship between damage variables of limestone and other mechanical parameters is analyzed.The study found that the damage variable is closely related to the hardness.The smaller the hardness,the greater the decrease in mechanical parameters.
作者
党发宁
高天晴
原诗晶
雷曼
DANG Faning;GAO Tianqing;YUAN Shijing;LEI Man(State Key Laboratory of Eco-hydraulics in Northwest Arid Region,Xi'an University of Technology,Xi'an,Shaanxi 710048,China)
出处
《岩石力学与工程学报》
EI
CAS
CSCD
北大核心
2022年第S02期3260-3270,共11页
Chinese Journal of Rock Mechanics and Engineering
基金
国家自然科学基金资助项目(51979225,51679199)
关键词
岩石力学
灰岩
化学腐蚀
纳米压痕试验
细观力学性质
rock mechanics
limestone
chemical etching
nano indentation test
meso-mechanical properties
作者简介
党发宁(1962-),男,1985年毕业于宁夏大学基础数学专业,现任教授、博士生导师,主要从事岩土工程数值分析、计算力学等方面的教学与研究工作。E-mail:dangfn@mail.xaut.edu.cn;通讯作者:高天晴(1997-),男,现为硕士研究生。E-mail:249950792@qq.com
