| Summary: | 碩士 === 國立臺北科技大學 === 土木工程系土木與防災碩士班 === 107 === The technical success of biomimetic mineralization has resulted in the nano-crystallization of calcium carbonate, whereby a hydrophobic concrete surface is obtained. So as to further explore the impact of biomimetic mineralization technology on the interior of concrete, this study conducted experiments with the addition of template and accelerated carbonation curing. In this way, it is expected to produce nano-calcium carbonate inside the concrete, and then explore its influence on the engineering properties of the concrete. For the test, the study used ordinary concrete (water-cement ratio of 0.6 and 0.8) and pervious concrete (slurry ratio of 0.09, 0.16 and 0.24) for research. Also, different template concentrations (0.1, 0.2, 0.3, and 0.5 %) were prepared and mixed in concrete. After pouring the concrete sample, biomimetic was performed at different mineralization temperatures and CO2 pressure (0~5 kgf/cm2)in mineralization processing. Subsequently, microstructure observation, compressive strength, water contact angle (WAC), weight change, acid resistance test, water permeability and porosity were tested to evaluate the effectiveness of mineralization technology in the internalization of concrete and the influence on the engineering properties.
It can be inferred from the test results that after the ordinary concrete is treated by biomimetic mineralization, the surface of the concrete had needle-like nano-calcium carbonate, and the shape of calcium carbonate inside the concrete was flake. Since ordinary concrete is denser, the shape change of calcium carbonate is less obvious. As for the pervious concrete, needle-like calcium carbonate formation was observed on the surface and at the deepest point. This result showed that there were many pores inside the pervious concrete, which could successfully modify the calcium carbonate inside the concrete. When the template concentration is 0.3 %, the temperature is 90 °C, and the CO2 pressure is changed to 0~5 kgf/cm2, the optimum compressive strength, contact angle (WAC), weight increase rate and durability can occur at a pressure of 5 kgf/cm2. The ordinary concrete strength is increased by about 28.5 %~34.6 %; the pervious concrete is about 56.4 %~59.7 %. The ordinary concrete has a contact angle of 103.6°~104.8°, which is a hydrophobic grade; the contact angle of porous concrete is 120°~120.3°, which is ultrahydrophobic. The weight gain rates of ordinary concrete (water-cement ratios of 0.6 and 0.8) were 1.28 % and 2.36 %, respectively. The above acid resistance increased by 56 % and 61 %, respectively. When the pervious concrete is at 90 °C and the pressure is 5 kgf/cm2, the water permeability and porosity are slightly lower. It can be seen that the mineralization treatment may fill the pores, and the water permeability and porosity may be slightly decreased.
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