摘要

本研究主要探討不同濕度試驗環境下鋼筋混凝土的碳化行為及其碳化後的力學行為與抗腐蝕能力。以固定水灰比（w/c = 0.6）製作混凝土試體，在飽和石灰水中養護28天後烘乾至恆重，再置於25℃、二氧化碳濃度50％的環境下，以不同的相對濕度（濕度循環70-90％、50-90％與定值濕度50％、70％和90％）加速混凝土碳化。

研究結果顯示：（1）在濕度循環的加速環境下碳化速率較定值濕度環境快。（2）經二氧化碳濃度修正後，濕度循環加速環境下所得之碳化係數與現地碳化係數較接近。（3）鋼筋混凝土在碳化後其力學性質包括抗壓強度、劈裂強度與握裹強度皆增加，與碳化深度成正比，但與加速環境的濕度無關。（4）鋼筋混凝土碳化使鋼筋越容易腐蝕，碳化深度越深則抗蝕能力衰減越明顯。

ABSTRACT
The purpose of this study is to explore the effects of humidity on the carbonation of the reinforced concrete and its associated mechanical properties and corrosion resistance. Concrete specimens with w/c of 0.6 were cured in saturated lime water for 28 days, oven-dried, and then put in accelerated environments with a constant temperature of 25 °C, CO2 concentration of 50% by volume, and various humidity environments, including constant humidities of 50%, 70%, and 90%, and cycling relative humidities ranging from 50% to 90%, or 70% to 90%. Results were summarized as follows. First, the cycling humidities induced higher carbonation coefficient than the constant humidity. Second, the converted carbonation coefficients determined by the cycling humidity environment were close to those determined from the onsite investigation. Third, the mechanical properties of the concrete were found increased by the carbonation. Fourth, the carbonation reduced the corrosion resistances of the reinforcements. Both the changes in the mechanical properties of the concrete and corrosion resistances of the reinforcements were associated with carbonation depth more than the relative humidities of the accelerated environment.

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