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徐变及饱和度对混凝土表面毛细吸水速率及气体渗透率的影响研究

发表时间:2017-01-23  浏览量:1373  下载量:383
全部作者: 邢秉元,周春圣,王振地
作者单位: 哈尔滨工业大学土木工程学院,结构工程灾变与控制教育部重点实验室;中国建筑材料科学研究总院,绿色建筑材料国家重点实验室
摘 要: 采用徐变加载的方法制备含有不同程度损伤的混凝土试件,利用气体渗透率和表面毛细吸水速率指标表征损伤混凝土试件的物质传输性能,研究徐变变形和初始饱和度对混凝土材料气体渗透率和表面毛细吸水速率这两个物质传输性能指标的影响。结果表明,长期荷载作用下产生的微裂纹等损伤将显著增大混凝土材料的气体渗透性和表面毛细吸水速率,卸载之后测量得到的本征气体渗透率和表面毛细吸水速率并不会随着徐变变形的增大而发生显著变化。混凝土材料的气体渗透率随饱和度的增大而快速减小,损伤程度较大的混凝土试件的气体渗透率对饱和度更敏感。所有饱和度为0.15左右的混凝土试件的表面毛细吸水速率均比干燥状态下的表面毛细吸水速率大;混凝土材料的表面毛细吸水速率指标对初始饱和度非常敏感。随初始饱和度的增加,表面毛细吸水速率逐渐减小并呈现明显的非线性性质。量化分析实际混凝土材料的耐久性时,须合理考虑损伤及饱和度的影响。
关 键 词: 建筑材料;气体渗透率;表面毛细吸水速率;饱和度;徐变;裂纹损伤
Title: Influence of creep and saturation degree on the capillary sorptivity and gas permeability of concrete
Author: XING Bingyuan, ZHOU Chunsheng, WANG Zhendi
Organization: Key Lab of Structures Dynamic Behavior and Control of the Ministry of Education, School of Civil Engineering, Harbin Institute of Technology; State Key Laboratry of Green Building Materials, Chinese Building Materials Science Research Institute
Abstract: In this paper, the effects of creep deformation and initial water saturation on mass transport properties of micro-cracked concrete materials are investigated. The long-term loading method is employed to prepare concrete specimens of different damage extent, whose mass transport properties are characterized by the gas permeability and capillary sorptivity. From the experimental results, it clearly indicates that the gas permeability and capillary sorptivity of concrete materials will dramatically increase due to the creep deformation caused by sustained loading action. However, the gas permeability and capillary sorptivity measured in unloading state are not significantly different for damaged specimens with various levels of creep deformation. On the other hand, the gas permeability of concrete materials rapidly decreases with the increase of saturation degree. The gas permeability for the concrete material with higher creep deformation is more sensitive to saturation degree. The capillary sorptivity of all concrete specimens with saturation degree of 0.15 is higher than that are initially dried to constant mass. In addition, the capillary sorptivity of concrete materials is very sensitive to initial saturation degree. The capillary sorptivity remarkably decreases with the increase of initial saturation in a manner of high nonlinearity. It is necessary to reasonably consider the obvious influences of loading damage and saturation degree on quantitative durability analysis for concrete materials under service.
Key words: building materials; gas permeability; surface capillary sorptivity; saturation degree; creep; cracking damage
发表期数: 2017年1月第2期
引用格式: 邢秉元,周春圣,王振地. 徐变及饱和度对混凝土表面毛细吸水速率及气体渗透率的影响研究[J]. 中国科技论文在线精品论文,2017,10(2):198-205.
 
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