円周切欠きを有する鉄筋コンクリート用棒鋼の低温下における脆性破壊発生特性に関する実験的研究

概要

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The purpose of this paper is to establish the evaluation method of the steel bars for concrete reinforcement to be used at low temperatures. The tensile tests of circumferentially notched specimens were carried out at low temperatures to investigate the brittle fracture initiation characteristics of the steel bars SD 35 having several strength levels. The results are summarized as follows; (1) The brittle fracture strength characteristics of the notched specimens have two patterns. One is called Ipattern showing the net stress at fracture, _nσ_B, increases with temperature lowering from room temperature to the temperature, T_L, at which low stress brittle fracture occures. The other is called D-pattern showing _nσ_B decreases monotonously at higher temperature than T_L. (2) These patterns have correlation with the lamellar structure consisting of ferite and pealite, and the pealite structure area percent. (3) Crystality transition temperatures, _vT_rs, of charpy impact tests have also corrlation with microstructures. (4) Brittle fracture initiation temperatures, T_i, of circumferentially notched specimens have correlation with _vT_rs. Then, T_i can be evaluated by _vT_rs. Finally, the method of the evaluation of the steel bars for concrete reinforcement considering the brittle fracture nitiation characteristics has been proposed in this paper.
社団法人日本建築学会の論文
1983-12-30