環境條件對混凝土結構物表面氯離子濃度入滲行為之研究

Abstract

台灣沿海地區高溫、潮濕，沿海橋梁受到環境影響，橋梁容易受到大氣中氯鹽離子影響。橋梁長期受到環境影響，形成裂縫氯離子藉由裂縫進入混凝土入中。氯離子滲入鋼筋混凝土結構中劣化原因。當鋼筋表面達氯離子臨界濃度時，鋼筋混凝土中鋼筋腐蝕混凝土產生裂縫，造成鋼筋握裹力下降，進而降低結構物撓曲強度。 文獻中現地曝放試驗試體多曝放於水下或潮汐間帶，混凝土試體較少曝放於沿海區域的大氣環境中。因此本研究採用飛來鹽份採集器收集大氣中氯鹽量。探討大氣中氯鹽量與混凝土中表面氯離子關係。 本研究希望藉由現地曝放試驗與鹽霧加速試驗，得知鹽霧加速試驗表面氯離子濃度表現與現地曝放試驗表面氯離子濃度表現。現地曝放試驗試體曝放立面角度不同，有0°、45°、90°、135°與180°。現地曝放試驗包含氣象因子資料，尋求表面氯離子濃度與氣象因子關係。

The weather is hot and humid in coastal region of Taiwan. Costal bridges affected by environment, bridges are susceptible to atmospheric influence of chloride ions. Bridges has been an environmental impact for a long time, the chloride ions penetration into the concrete of cracks. Whenever the threshold amount of chloride at the surface of reinforcement is reached, reinforcement corrosion and concrete cracking may occur resulting in decreasing the bond strength between concrete and reinforcement,and subsequently reducing the flexural or shear strength of the structure. Situ exposures most discuss test specimen placeing in water or exposed to tidal zone, less exposed concrete specimen in the coastal zone atmosphere in literature. Therefore, this study uses spray salt collectors collect chloride from marine aerosol. The relationship between chloride from marine aerosol and surface chloride of concrete is discussed in this paper. The paper hopes to find the relationship between field test and salt spray test. Release the relationship between surface chloride of field test and surface chloride of spray salt test. Field exposure test discuss test side of speciments exposed to different angle, there are 0 °, 45 °, 90 °, 135 ° and 180 °. The field test comprised environmental characterisation. Find the relationship between environmental characterization and surface chloride.