Tension Stiffening Affected by Radiation-induced Volume Expansion of Aggregate Daisuke Kambayashi, Ippei Maruyama, Osamu Kontani, Shohei Sawada, Takahiro Ohkubo, Kenta Murakami, Kiyoteru Suzuki https://doi.org/10.3151/jact.21.351

中性子の照射環境にあるコンクリートは骨材の膨張によって劣化が生じると考えられています。その中で、鉄筋とコンクリートの付着に及ぼす影響について、理解は進んでいません。そこで、RBSMを用いて骨材を膨張させて、両引き試験を行ってテンションスティフニングを評価し、どの程度の範囲で健全性が担保されているかを議論しました。

The tension stiffening behavior of reinforced concrete (RC) prisms, affected by the aggregate volume expansion induced by neutron irradiation, were numerically investigated using a rigid body spring network model. First, the model was validated by comparison with the uniaxial tension test results of wet- and dry-cured (with volume contraction of concrete) RC prisms. Subsequently, different degrees of expansion strain were applied to the aggregate elements in the RC prism model and the uniaxial tension loading was simulated again. Tension stiffening decreased under larger radiation-induced volume expansion of the aggregate owing to the corresponding decrease in the concrete tensile strength with increasing damage, this behavior changed considerably according to the restraint condition. Indeed, the Young’s modulus of the restrained concrete after aggregate expansion was larger than that of the unrestrained concrete after aggregate expansion. However, the compressive stress in the concrete after aggregate expansion was effectively transmitted to the rebar during uniaxial tension loading; this behavior indicated that RC could maintain its integrity under uniaxial tension even after 0.5% aggregate linear expansion.