混凝土內鋼筋腐蝕與氯離子濃度之研究

Abstract

本研究係透過調整水膠比(0.35、0.45、0.55、0.65)，及數種卜作嵐材料添加率(飛灰取代水泥10%、20%、30%；爐石取代水泥15%、30%、50%)，以探討不同的配比對混凝土耐久性之影響；利用Salt Ponding Test模擬試體曝露於氯鹽環境的情況，藉以觀察混凝土抵抗氯離子入侵，進而使鋼筋免受腐蝕危害的能力。而判斷混凝土內鋼筋的腐蝕狀況是使用美國James儀器公司製作的 Gecor 8 腐蝕電流儀進行試驗；量測鋼筋的腐蝕電流密度、腐蝕電位與混凝土電阻係數，作鋼筋腐蝕趨勢的一直接指標；並對試體進行抗壓強度試驗、氯離子含量滴定試驗及酸鹼滴定試驗，以作為混凝土對鋼筋保護程度之參考。

The subject of the thesis is to study the effect of different mix proportion on the durability of concrete through setting several w/b ratio (0.35, 0.45, 0.55, 0.65) and pozzolanic material substitution (fly ash replaces cement for 10%, 20%, 30%; slag replaces cement for 15%, 30%, 50%). Salt ponding test was conducted to simulate the situation of exposure to chloride of specimen, and to judge the ability of concrete of resisting chloride permeation and the capability of protecting reinforcing steel from corrosion. Besides, Gecor 8, made by James Instruments, was used to determine the corrosion trend of the reinforceing steel in concrete by measuring the corrosion rate, corrosion potential and electrical resistance. Furthermore, concrete compressive strength test, chloride ion content titration and acid-base titration were conducted to judge the degree of reinforcing steel protection by concrete.