养护条件对混凝土早期氯离子扩散系数的影响  

Impact of curing condition on concrete chloride ion diffusion coefficient of early age

作　　者：宋东升[1,2] 张巨松[1] 邓嫔[1] 

机构地区：[1]沈阳建筑大学材料科学与工程学院,辽宁沈阳110168 [2]沈阳泰丰特种混凝土有限公司,辽宁沈阳110002

出　　处：《混凝土》2010年第7期25-27,共3页Concrete

基　　金：建设部科技攻关项目(2007-k4-19);沈阳地铁混凝土攻关项目

摘　　要：采用NEL法测试了不同养护条件下、不同矿物掺合料及掺入硫酸钠(Na2SO)4的混凝土早期氯离子扩散系数,结果表明:掺Na2SO4后干空养护基准混凝土的Cl-扩散系数上升,容易发生干缩开裂;在养护过程中改变养护条件即在3、7、14d中止标准养护转入干空养护后,混凝土Cl-扩散系数都不同程度的增大;在干空养护条件下,粉煤灰的掺入影响了混凝土的水化过程,使混凝土内部结构发展不密实;Na2SO4的掺入可激发粉煤灰的二次水化反应,使其Cl-扩散系数较未掺的低;矿粉混凝土具有较好的水化活性,在干空养护条件下,其内部结构发展速度也较快;试验结果同时也表明矿粉的活性较粉煤灰高。The early age chloride ion diffusion coefficient of the concrete,which is during different curing condition,adulterated with different mineral admixture and sodium sulfate,is tested by the method of NEL;The test result indicates that the chloride ion diffusion coefficient of reference concrete adulterated with sodium sulfate under the curing condition of dry air is higher,and the concrete is easy to engender：dry-shrinkage cracking;the chloride ion diffusion coefficient of reference concrete is to varying degrees higher,when the curing condition is varietal during curing period,that is to turn standard curing to curing condition of dry air at the curing age of 3 days,7 days and 14 days;During the curing condition of dry air,adding concrete to fly ash affects the hydration process of concrete and makes that the structure of concrete is not compact;Adding concrete to sodium sulfate motivates the second hydration reaction of fly ash and makes the chloride ion diffusion coefficient of the concrete is higher than that without adding sodium sulfate;Concrete adulterated with mineral powder has a preferable hydraulicity and its structure has a quick development;At the same time,the test result indicates that the mineral powder is more active than fly ash.

关 键 词：粉煤灰 矿粉 硫酸钠 氯离子扩散系数 养护条件 

分 类 号：TU528.01[建筑科学—建筑技术科学]