气泡结构特征对混凝土抗盐冻性能的影响  

Influence of Structural Characteristics of Air Bubbles on Salt Frost Resistance of Concrete

作　　者：张云清[1] 余红发[1] 王甲春[1] 

机构地区：[1]南京航空航天大学土木工程系,江苏南京210016

出　　处：《华南理工大学学报（自然科学版）》2010年第11期7-11,共5页Journal of South China University of Technology(Natural Science Edition)

基　　金：国家"973"计划项目(2009CB623203);中国博士后基金资助项目(20060400284);江苏省博士后基金资助项目(0602018B);南京航空航天大学博士生创新基金资助项目(BCXJ07-04)

摘　　要：采用快冻法研究普通混凝土、引气混凝土和高性能混凝土在3.5%(质量分数)的NaC l溶液中的抗盐冻性能以及混凝土抗盐冻性能与气泡特征参数间的关系.结果表明:当引气剂的品种确定后,混凝土的气泡平均间距(L-)和气泡平均直径(D-)在很大程度上依赖于含气量,含气量越高,L-和D-越小;矿物掺合料对混凝土的气泡结构特征及其规律性并没有明显的影响;掺引气剂是提高混凝土抗冻融破坏能力的有效手段,同一般冻融环境中混凝土的普通抗冻性一样,含气量对抗盐冻性的影响也存在一个临界范围,在普通冻融环境中,混凝土的临界含气量为2.0%～3.0%,盐冻环境下临界含气量提高到4.5%～5.0%;高性能混凝土具有良好抗盐冻性所要求的气泡平均间距与强度等级有关,在强度等级低于C50时,混凝土的气泡平均间距必须小于250μm,当强度等级提高到C60以上时可增大到700μm.The salt frost resistance,as well as the relationship between the salt frost resistance and the air bubble parameters,is investigated by means of the accelerated freeze-thaw method for common concrete,air-entrained concrete and high-performance concrete under the action of 3.5%（mass fraction） sodium chloride solution,respectively.The results show that the average spacing factor（） and bubble diameter（） of concrete is largely dependent on air content in a negative relation when the air-entraining agent is determined,that mineral admixture has no significant influence on the bubble characteristics of concrete and its regularity,that adding air-entraining agent is an effective means of improving the anti-freeze-thaw performance of concrete,and that there also exists a critical air content of concrete the same as common freeze-thaw performance,which is 2.0%～3.0% in common freeze-thaw environment and rises to 4.5%～5.0% in salt freezing environment.Moreover,it is found that the average spacing suitable for the salt frost resistance of high-performance concrete is related to the strength grade of concrete,and should be less than 250 μm when the strength grade of concrete is less than C50.Meanwhile,it can rise to 700 μm when the strength grade is greater than C60.

关 键 词：高性能混凝土 引气剂 引气混凝土 抗冻性能 气泡 结构特征 冻融循环 

分 类 号：TU528[建筑科学—建筑技术科学]