混凝土界面过渡区水分传输特性试验研究

Experimental study on moisture transport property of interfacial transition zone in concrete

设计制作了一批圆柱形水泥砂浆试件和混凝土试件,通过水分传输试验获取各试件的平均水分传输系数,引入界面过渡区(ITZ)与砂浆基体水分传输系数的比值β,再根据混凝土试件的并联传输模型反算获得β值。研究了截面形式、砂浆水灰比、砂灰比、粗骨料材质、表面粗糙度等因素对β值的影响。试验结果表明:ITZ与砂浆基体水分传输系数的比值β在90～175的范围内;截面形式相同时,花岗岩质粗骨料表面不进行处理时的β值均比进行喷砂处理时的β值大;β值随着砂浆水灰比的变化无明显变化,随着砂浆砂灰比的增大而减小;截面形式及砂浆配合比相同时,β值的大小不仅与骨料表面粗糙度相关,还与骨料材质相关。

A group of cylindrical cement mortar specimens and concrete specimens were designed and manufactured, and the average moisture transport coefficients of these specimens were obtained through moisture transport experiments. The value of β, which was introduced as the ratio between the moisture transport coefficients of interfacial transition zone(ITZ) and mortar matrix, was acquired by the parallel transport model of concrete specimens. Furthermore, influences of the water-cement ratio and sand-cement ratio of mortar matrix, the material and surface roughness of coarse aggregates on the value of β were studied. As the results indicate, the value of β ranges from 90 to 175. When the granitic coarse aggregate surface is original, the value of β is larger than that when the surface is sandblasted, and β remains about the same when water-cement ratio changes, however decreases with the increment of sand-cement ratio of mortar matrix. Furthermore, when the cross section type and mix proportion of cement mortar are uniformed, the value of β depends on both surface roughness and material type of coarse aggregate.