二氧化碳養護對混凝土性質影響之研究

This research used two concrete strengths included three different sizes with ϕ5×10 cm, ϕ10×20 cm and ϕ15×30 cm to compare with each other. After casted in cylinder model for four hours in air to finish initial setting program, removed form immediately then put specimens into pressure chamber which injected the high carbon dioxide gas to start doing the fast curing test with factors included three carbon dioxide concentrations, three curing time and two curing pressures. Finally, put CO₂ -cured specimens in the saturated limewater to keep after curing. This research includes compressive strength, elastic modulus, rupture modulus and carbonated depth for different cylinder concrete sizes in different environment factors of CO₂ curing. According to the result, the best compressive strength of the ϕ15×30 cm specimen is about 100% of carbon dioxide concentration, 1 hour of curing time, 2 bar(kgf/cm^²) of curing pressure. When the curing day came to 3, 7, 28 and 90, the compressive strength of the CO₂ -cured specimens were higher than the hydraulic specimens about 29%, 38%, 8% and 11%. The elastic modulus and rupture modulus of CO₂ -cured specimens had less difference in 5% with hydraulic specimens and the CO₂ -cured specimens had carbonated depth about 1.17 mm. According to the result, the compressive strength will be stronger after CO₂ curing. The CO₂ -cured specimens have carbonated depth phenomenon and the elastic modulus and rupture modulus have less effect by CO₂ curing.