Evaluation of water transfer from saturated lightweight aggregate to cement paste matrix by neutron radiography

中性子ラジオグラフィを用いた飽和軽量骨材からセメントペーストマトリックスへの水分移動の評価

丸山 一平*; 兼松 学*; 野口 貴文*; 飯倉 寛  ; 寺本 篤史*; 早野 博幸*

Maruyama, Ippei*; Kanematsu, Manabu*; Noguchi, Takafumi*; Iikura, Hiroshi; Teramoto, Atsushi*; Hayano, Hiroyuki*

In high-strength concrete with low water-cement ratio, self-desiccation occurs due to cement hydration and causes shrinkage and an increased risk of cracking. While high-strength concrete has a denser matrix than normal-strength concrete, resulting in lower permeability, early-age cracks would cancel out this advantage. For the mitigation of this self-desiccation and resultant shrinkage, water saturated porous aggregate, such as artificial lightweight aggregate, may be used in high-strength concrete. In this contribution, for the purpose of clarification of the volume change of high-strength concrete containing water-saturated lightweight aggregate, water transfer from the lightweight aggregate to cement paste matrix is visualized by neutron radiography. As a result, it is clear that water was supplied to the cement paste matrix in the range 3-8 mm from the surface of the aggregate, and the osmotic forces may yield water transfer around lightweight aggregate in a few hours after mixing.