Study on formation and quantification of quality of the fragile layer of a concrete surface

众所周知，混凝土表面易碎层是受渗水和环境条件的影响而形成的，是造成混凝土表层与混凝土内层质量差异的主要原因。在本研究中，考虑影响表面脆性层形成的因素是构件截面的厚度，并在此假设下进行实验。随着构件截面的增加，易碎表面层的成形似乎受到出血的影响，并且在靠近模具的区域变得最明显。构件截面厚度越大，其表面强度、透气性、抗结垢性和碳化性差异越大。结果表明，构件截面厚度的不同对混凝土表面构件的强度和耐久性产生较大的影响。

It is widely known that the surface fragile layer of concrete is formed by the influence of bleeding and environmental conditions, and that it causes the difference in quality between the surface layer of concrete and the inner layer of concrete. In this study, the factor which was considered to have an influence on the forming of surface fragile layer was the thickness of the member section, and on this hypothesis the experiment was conducted.Bleeding which seems to influence the forming of the fragile surface layer as the member section increased and became most noticeable in the areas near the mold. The more the thickness of the member section was increased, the greater the difference in the surface strength, the permeability, scaling resistance and carbonation, respectively. As a result, it was shown that the strength and durability of a concrete surface part produce a big difference by difference of the thickness of a member section.