ケイ酸質塗布防水材料によるコンクリートの内部組織の変化 : 湿潤環境下における防水工法の研究・その1

抄録

This paper deals with change in microstructure of concrete by siliceous coating. Two types of coatings, one is inorganic powder mixed with water and the other inorganic powder mixed with polymer emulsion, were used for the experiment. Water pressure was given on either the coated surface or the opposite side, and the nocoated specimen was also included for comparison. Two types of concrete, water/cement ratios of 0.55 and 0.70 by weight, were adoppted as substratum. For estimation on the effect of siliceous coating, crystal growth in microstructure was periodically observed through SEM until two years, and chemical components of crystals were analyzed with EDX and X-ray diffraction. The results of this study can be summarized as follows. 1) The effect of coatings on the growth of crystals reached into 2〜2.5mm from the coated surface, and the higher water/cement ratio of concrete, the more deep it reached. 2) The effect reached deeply in the specimen given water pressure on the coated surface than it given on the oppsite side. 3) Crystals grew larger and denser in microstructure, and changed into a plate or block type in progress of time. 4) Based on the EDX and X-ray diffraction, fibrous crystal mainly consists of Ca and Si, and it is concluded to be calcium silicate hydrate. Needle crystal consists of Al, Si, S and Ca, and it to be ettringite.