膠化瀝青塗層對鋼筋混凝土梁之防蝕效益探討

A Study of Rubberized Asphalt Coating on the Steel Bar to Provent Corrosion of Reinforced Concrete Beam

本研究主要探討採用膠化瀝青塗層對混凝土中鋼筋之保護效果。探討變數為鋼筋塗佈膠化瀝青與否，並於靜態與反覆載重下，裂縫變數對混凝土梁中鋼筋腐蝕行為之探討。本研究混凝土依ACI 318-89規範，以緻密配比法（DMDA）設計0.4水灰比強度（f’c）＞5000 psi。試驗結果顯示：混凝土梁開裂前，混凝土保護層提供良好的保護效果，使鋼筋免於腐蝕。然而，混凝土梁開裂後，混凝土保護層不再提供鋼筋長期保護，鋼筋立刻被腐蝕，在這種情況下，膠化瀝青塗層就能抑制鋼筋腐蝕。

This study is mainly to investigate the effect of rubberized asphalt coating on the corrosion prevention of steel embedded in ordinary Portland cement concrete beam. The parameters are whether the steel bar coated with rubberized asphalt or not, as well as the corrosion behavior of steel embedded in concrete beam under static and repeated loading. The concrete beam is designed according to ACI 318-89 code with the requirement of w/c ratio less than 0.4 and f'c > 5000 psi , and by densified mixture design algorithm (DMDA). The test results indicate that before concrete crack, the concrete cover provide excellent protection effect to prevent the steel from corrosion. However, after beam cracked, the concrete protection layer no longer provides protection for steel, and it is corroded immediately. In such case, the rubberized asphalt coating then takes turn to prevent the steel from corrosion.