| Summary: | 碩士 === 國立海洋大學 === 河海工程學系 === 87 === This study is to investigate the carbonation and its effect on concrete properties. Accelerated testing methods were applied to evaluate the carbonation factors such as environmental relative humidity and water/cement ratio and etc. Mechanical tests, physical tests, chemical tests, electrochemical tests, and SEM test were conducted.
Test results show that concrete carbonation may improve the compressive strength, splitting tensile strength, rebar bond strength and surface hardness. However, whenever the carbonation depth reaches the vicinity of rebar the half-cell potential significantly drops and the corrosion rate increases. A dense pore structure in the carbonated area was observed through SEM analysis and CaCO3 compound was detected to verify the carbonation depth using X-ray diffraction analysis.
It appears that the carbonation depth increases as the water/cement ratio increases and the specimens with a w/c ratio of 0.6 under 50% relative humidity have the fastest carbonation rate. In addition, the two-end coated specimens had larger carbonation depth than the side-surface coated specimens.
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