報告書番号

N15003

タイトル（和文）

ひび割れ損傷を有する鉄筋コンクリートはり部材の塩害劣化と耐荷特性評価に関する検討

タイトル（英文）

Evaluation on effects of chloride-induced deterioration on mechanical properties of RC beams with cracking damage

概要 （図表や脚注は「報告書全文」に掲載しております）

本研究では，RCはり部材に生じるひび割れ損傷などが，塩害劣化や耐荷特性に及ぼす経年的な影響を評価するとともに，その考慮方法を提案した。まず，実験により，初期損傷が鉄筋降伏直後(残留ひび割れ幅0.4mm程度)であれば，ひび割れの有無が腐食進行に及ぼす影響は小さいこと，かぶり剥落を模擬し場合には，局所的な腐食が顕著になる傾向にあり，鉄筋が破断することにより，曲げ耐力は約7%に低下することなどが示された。次に，鉄筋腐食量と経過時間の関係に関する実験結果に基づいて，ひび割れ損傷を考慮した鉄筋の腐食速度を算定した。さらに，既提案の材料劣化の力学モデルに，腐食に伴う鉄筋の伸び性能の低減を考慮することにより，鉄筋腐食が生じたRC部材の耐荷特性を評価可能であることが確認された。

概要 （英文）

This paper discusses the influence of chloride-induced deterioration on mechanical properties of aging reinforced concrete (RC) structures and the applicability of the material degradation model that takes reinforcing steel corrosion into consideration for finite element analysis.
We conducted the corrosion tests under the simulated tidal environment and the flexural loading tests for the RC beams with cracking damage and initial defects. Then, the experimental results were numerically correlated to validate the devised modeling.
The obtained results were summarized as follows:
(a) The cracking damage in specimens caused a minor effect on the reinforcing steel corrosion in the case where the thickness of cover concrete was 40mm and main rebars did not yield before chloride attack. On the other hand the maximum corrosion ratio of the deteriorated part became considerably larger than that of the non-cracking part in the specimens where the cover concrete were removed partially to simulate spalling by the severe corrosion.
(b) Based on the test results, we derived the corrosion velocity of reinforcing steel corresponding to cracking damage degrees.
(c) In FEM analyses, we showed that the above modeling can estimate the flexural strength of RC beams in consideration of the degradation in elongation performance of reinforcing steel due to corrosion.

報告者

キーワード