Research Of Carbon Dioxide Concrete Curing Technology

As a very promising technology, Carbon dioxide concrete curing technology has a great infect on the greenhouse gas emission reduction and concrete material science. Carbon dioxide concrete curing technology and the influence of calcium carbonate were studied in this thesis. Major work and conclusions in this paper are as follows:1. Pre-curing conditions are extremely important in increasing the extent of CO2 uptake and the compressive strength of concrete specimens. Pre-curing conditions not only affects the moisture content, water loss rate, also affect the residual water/cement ratio. In this study, when the pre-curing time control in 2～6h, the extent of CO2 uptake of concrete specimens was appropriate.2. Varieties of cement have a great impact on the extent of CO2 uptake and the compressive strength. Test results shows that the extent of CO2 uptake of P.I Portland Cement higher 10～15% than P.O Portland cement, and the compressive strength is twice than the Shaofeng cement.3. After the pre-curing measures, water/cement ratio affects the extent of CO2 uptake less than the effevtive water/cement ratio. The effevtive water/cement ratio is the important parameter in Carbon dioxide curing concrete technology. When the water/cement ratio is 0.28～0.42, the difference of the extent of CO2 uptake controlled in 5%, the difference of compressive strength controlled in 4MPa. In this study, when the water/cement ratio control in 0.32～0.36, the effevtive water/cement ratio control in 0.15～0.20 by all the way, the extent of CO2 uptake of concrete specimens was appropriate.4. Molding preesure has little affect on the extent of CO2 uptake and the compressive strength. When the extent of CO2 uptake was appropriate, the smaller the molding pressure, the better the extent of CO2 uptake.5. It was not affected by prolonging the pre-curing time, nor by the CO2 curing time. When the CO2 curing time control in 2h, the extent of CO2 uptake of concrete specimens was appropriate.6. The extent of CO2 uptake could be increased by adding calcium carbonate, when the dosage of calcium carbonate was 6% of the cement quality, the extent of CO2 uptake of concrete specimens was maximum. Nevertheless, the compressive strength of concrete specimens will reduce when adding calcium carbonate powders. The more the dosage of calcium carbonate, the lower the compressive strength of concrete specimens. The fineness of calcium carbonate has little affect on the extent of CO2 uptake and the compressive strength of concrete specimens.