Batsaikhan TSENGELMAA

Experimental study on spatial distribution of water permeability of concrete in structure

Takumi SHIMOMURA
 The purpose of this survey is to grasp the material permeation resistance due to the difference in the position in the concrete structure by the water absorption test. In order to confirm whether or not there is a difference in the substance permeation resistance depending on the position of the concrete structure, a surface water absorption test was regularly performed from three different places of the specimen. In order to confirm the effect of bleeding, two test specimens were prepared using the two formulations.
  From the results of the water absorption test in this study, the following became clear. The material permeation resistance of concrete differs depending on the position, and becomes lower as it is closer to the casting surface. When the bleeding occurs, the resistance to the substance permeation in the concrete is more influenced by the difference in the composition than in the position.
 In the void test, it can be seen that the void amount of the specimen close to the top surface is larger in both formulations than in other positions. In addition, the porosity in the part where bleeding occurred was the largest. However, the spatial difference was larger in Formulation 2, and the difference in the void volume due to Formulation was not so large. 
 To confirm how much the substance permeation resistance has changed due to bleeding, a reproducible analysis of the water absorption behavior was performed. At the time of reproduction analysis, the difference in position was expressed by changing the parameters of the pore structure based on the experimental results. At this time, the parameter V0 was identified from the experimental results, and B and klp were determined from the parameter study.
 Looking at the results of the parameter B is small only in the part due to bleeding. It was suggested that bleeding had a greater effect on increasing the pore size than increasing the pore volume.