轴压荷载作用对混凝土微裂缝和渗透性影响研究  

Research on the micro- crack and permeability of concrete under axial compressive load

作　　者：刘洪珠[1] 赵铁军[1] 曹承伟[2] 陆文攀[1] 代鑫旖 

机构地区：[1]青岛理工大学土木工程学院,山东青岛266033 [2]同济大学建筑工程系,上海200092

出　　处：《混凝土》2016年第3期1-4,11,共5页Concrete

基　　金：国家重点基础研究发展计划"973"项目(2015CB655100);国家自然基金重点国际合作项目(51420105015)

摘　　要：通过对水灰比0.4的普通混凝土棱柱体试件进行65%、75%、85%三种轴压应力水平下的持载1 250 min试验,测定了整个加载、持载和卸载过程中的纵横向应变,并引入比裂缝面积评价轴压荷载作用下混凝土损伤。同时,对卸载后的混凝土试件进行毛细吸水和吸盐试验,评定不同荷载水平下混凝土的渗透性能。试验结果表明:轴压荷载作用下,混凝土纵向、横向应变均随着应力水平的增加而变大;较高的应力水平下,混凝土完全卸载后,由于其内部出现一定损伤,应变不会完全恢复,仍残留一部分的塑性变形;混凝土内部的水分及氯离子量均随着轴压荷载的增加而变大,并且在较高应力水平下,横向毛细吸收系数和氯离子扩散系数均大于纵向毛细吸收系数和氯离子扩散系数。It used ordinary concrete prism of 0. 4 water cement ratio,and the specimens were sustained for 1 250 minutes under three kinds of axial compressive stress level with 65%,75% and 85% to determine longitudinal and transverse strain in the whole load,sustained load and unload process,special crack area was used to evaluate the damage in concreteunder axial compressive load. M eanwhile,after unload,the permeability was measuredat different stress. Results showthat longitudinal strain and transverse strain of concrete growwith the increase of stress levelunder axial compressive load. After the specimens unload in high stress,the strain will not fully recover and still remain part of the plastic deformation due to its internal certain damage. The content of water and chloride ion inside the concrete increases with the increase of the axial compression load,and the capillary absorption coefficient and chloride ion diffusion coefficientin the horizontalare all greater than ones in the vertical under high stress level.

关 键 词：轴压荷载 比裂缝面积 微裂缝 毛细吸收 氯离子扩散 

分 类 号：TU528.01[建筑科学—建筑技术科学]