維持・管理／検査技術・診断 (3)

[VI-144] Research Regarding the Use of Near-Infrared Spectroscopy to Estimate Chloride Ion Concentration in Prestressed Concrete Grouting

*山本 晃臣¹、上田 隆雄²、野島 昭二³、渡邉 晋也⁴、渡瀬 博⁵ (1. （株）フジタ建設コンサルタント、2. 徳島大学大学院社会産業理工学研究部、3. 中日本高速技術マーケティング（株）、4. （一社）日本建設機械施工協会　施工技術総合研究所、5. オリエンタル白石（株）)

Keywords:near-infrared spectroscopy, prestressed concrete grouting, chloride ion

Recent investigations of existing prestressed concrete bridges have identified voids due to incomplete grouting. Usually re-grouting is used as a countermeasure, however, grouting in bridges that have been exposed to anti-freezing agents or airborne sea salt particles may contain a high concentration of chloride ions, and the introduction of new grout material may lead to macrocell corrosion of prestressing cables. In this investigation, mock grouting specimens were produced and the use of near-infrared spectroscopy to estimate chloride ion concentration as an evaluation method was considered. Additionally, the suitability of this method for the testing of existing bridges was considered.