Calculation of Internal Humidity Field of Concrete Based on ANSYS
-
摘要: 为利用通用有限元程序温度场模块计算混凝土内部湿度场,对比了温度场和湿度场的微分方程、初始及边界条件,提出了有限元程序ANSYS温度场模块计算混凝土湿度场的有限元方法,并基于既有混凝土内相对湿度测试试验结果,从自干燥效应和干燥效应两方面对该方法进行了验证,分析了影响湿度场分布的内部水分自耗函数、湿度扩散系数和表面水分转移系数的参数取值,得到了水分自耗率公式.研究结果表明:湿度场计算中的相对湿度、湿度扩散系数、湿度自降低项和表面水分转移系数可分别用温度场计算中的温度、导温系数、绝热升温函数和换热系数表示;用温度场模块分析混凝土的湿度场结果与既有试验结果的最大误差为7.3%,满足工程要求;获得的水分自耗率公式可适用于水灰比为0.28~0.68的混凝土湿度场计算.Abstract: In order to calculate the humidity field of concrete using the temperature field module in finite element program, a comparison between thermal field and humidity field was made of their differences in the differential equations, initial and boundary conditions, etc. Based on the temperature field module in ANSYS, a finite element method was proposed to calculate the humidity field in concrete. From the aspect of self-desiccation and desiccation, this method was verified against the existing test results of the relative humidity in concrete. The values of parameters for ANSYS analysis such as the coefficients of the internal moisture consumption function, moisture diffusion coefficients, and surface factors which affect the humidity field in concrete were analyzed. The results show that the relative humidity, diffusion coefficients, self-desiccation formula, and the coefficient of moisture transfer in surface used in the humidity field calculation can be replaced by the temperature, thermal diffusivity, adiabatic heating function, and the heat transfer coefficient used in the temperature field calculation. Using the temperature field module to analyze the humidity field in concrete, the maximum error between the calculated results and the existing test results is 7.3%, which meets the engineering requirements. The self-desiccation formula obtained from the experimental results can be applied to the moisture field calculation of the concrete with a water cement ratio ranging from 0.28 to 0.68.
-
Key words:
- concrete /
- humidity field /
- finite element /
- diffusion coefficients /
- self-desiccation
-
XI Y, BAZANT Z P, MOLINA L, et al. Moisture diffusion in cementitious materials moisture capacity and diffusivity[J]. Advanced Cement Based Materials, 1994, 1(6):258-266. 高原. 干湿环境下混凝土收缩与收缩应力研究[D]. 北京:清华大学土木工程系,2013. 刘鹏,余志武,王卫仑,等. 模拟环境中混凝土与环境间水分传输边界条件[J]. 中国公路学报,2015,28(5):108-116,124. LIU Peng, YU Zhiwu, WANG Weilun, et al. Moisture transmission boundary condition between concrete and artificial simulation environment[J]. China Journal of Highway and Transport, 2015, 28(5):108-116,124. AKITA H, FUJIWARA T, OZAKA Y A. Practical procedure for the analysis of moisture transfer within concrete due to drying[J]. Magazine of Concrete Research, 1997, 49(179):129-137. KIM J K, LEE C S. Prediction of differential drying shrinkage in concrete[J]. Cement and Concrete Research, 1998, 28(7):985-994. YUAN Y, WAN Z. Prediction of cracking within early-age concrete due to thermal, drying and creep behavior[J]. Cement and Concrete Research, 2002, 32(7):1053-1059. PARROTT L. Moisture profiles in drying concrete[J]. Advances in Cement Research, 1988, 1(3):164-170. WONG S F, WEE T H, SWADDIWUDHIPONG S, et al. Study of water movement in concrete[J]. Magazine of Concrete Research, 2001, 53(3):205-220. 王建,戴会超,顾冲时. 混凝土湿度运移数值计算综述[J]. 水力发电学报,2005,24(2):85-89. WANG Jian, DAI Huichao, GU Chongshi. Summary on numerical calculation of moisture transfer in concrete[J]. Journal of Hydroelectric Engineering, 2005, 24(2):85-89. 龚灵力. 自密实混凝土性能及混凝土多场耦合时变性分析研究[D]. 杭州:浙江大学建筑工程学院,2010. 彭友松. 混凝土桥梁结构日照温度效应理论及应用研究[D]. 成都:西南交通大学土木工程学院,2007. SAKATA K. A study on moisture diffusion in drying and drying shrinkage of concrete[J]. Cement and Concrete Research, 1983, 13(2):216-224. 蒋正武,王培铭. 等温干燥条件下混凝土内部相对湿度的分布[J]. 武汉理工大学学报,2003,25(7):18-21. JIANG Zhengwu, WANG Peiming. Internal relative humidity distribution of concrete under isothermal drying conditions[J]. Journal of Wuhan University of Technology, 2003, 25(7):18-21. KIM J K, LEE C S. Moisture diffusion of concrete considering selfdesiccation at early ages[J]. Cement and Concrete Research, 1999, 29(12):1921-1927. Comite EuroInternational Du Beton. CEB-FIP model code 1990[S]. Lausanne:Thomas Thelford, 1993. 张君,侯东伟. 基于内部湿度试验的早龄期混凝土水分扩散系数求解[J]. 清华大学学报:自然科学版, 2008,48(12):2033-2035,2040. ZHANG Jun, HOU Dongwei. Calculation of moisture diffusion coefficient in early age concrete from interior humidity tests[J]. Journal of Tsinghua University:Science Technology, 2008,48(12):2033-2035,2040. 马跃先,陈晓光. 水工混凝土的湿度场及干缩应力研究[J]. 水力发电学报,2008,27(3):38-42. MA Yuexian, CHEN Xiaoguang. Research on humidity and drying shrinkage stress of hydraulic concrete[J]. Journal of Hydroelectric Engineering, 2008, 27(3):38-42.
点击查看大图
计量
- 文章访问数: 620
- HTML全文浏览量: 100
- PDF下载量: 447
- 被引次数: 0