粉煤灰对混凝土内外层非均匀收缩的影响  

Effect of Fly Ash on Differential Shrinkage Between the Outer and Inner Concrete

作　　者：高小建[1] 杨英姿[1] 阚雪峰[1] 

机构地区：[1]哈尔滨工业大学土木工程学院,黑龙江哈尔滨150006

出　　处：《应用基础与工程科学学报》2010年第1期91-97,共7页Journal of Basic Science and Engineering

基　　金：国家自然科学基金资助项目(50408016);中国博士后科学基金资助项目(20060400825)

摘　　要：采用多组LVDT位移传感器,研究了单面干燥条件下不同粉煤灰掺量的混凝土距离表面不同深度处的收缩变形,同时采用埋置湿度传感器的方法测试了不同深度层混凝土中相对湿度变化.结果表明:单面干燥条件下,各混凝土中均存在明显的内外层收缩差和湿度梯度差,且这种收缩变形差随干燥龄期的延长逐渐增大.距离干燥表面任一深度处,混凝土的最终收缩变形和单位相对湿度降低引起的收缩值均随粉煤灰的掺入而减小.掺粉煤灰使混凝土的内外层收缩变形差在开始一周内的增长速率加快,但却使最终收缩梯度差变小.Shrinkage strain of concrete containing different depths from the drying surface by using several pairs one surface of the concrete specimen was exposed amount of fly ash was measured at various of LVDT displacement sensors, and only to dry condition during the experiment. Relative humidity development of concrete at various depths from the exposed surface was also studied by using embedded humidity sensors. The results showed that remarkable shrinkage strain and relative humidity difference formed according to the depth from the exposed surface for every concrete, and such differential shrinkage increased with the drying time. At each depth from the drying surface, the addition of fly ash decreased the total shrinkage deformation and shrinkage strain induced by per unit of relative humidity reduction in concrete. The addition of fly ash accelerated the development of differential shrinkage of concrete according to depth from the exposed surface during the first one week of drying, but decreased the final shrinkage difference in concrete.

关 键 词：混凝土 单面干燥 非均匀收缩 粉煤灰 

分 类 号：TU528[建筑科学—建筑技术科学]