Processes and systems for carbon dioxide sequestration and related concrete compositions
A ready-mixed composition and a pre-mix composition for the production of a concrete material containing sequestered carbon dioxide, a CO 2 -containing water used in such compositions, dry-batch and wet-batch processes for sequestering carbon dioxide in concrete material, general method and process for sequestering carbon dioxide in hardening concrete, system and ready-mixed truck to perform such processes and methods for the production of a ready-to-cure carbonated concrete. Compositions comprise a concrete mixture and a CO 2 -containing water. The CO 2 -containing water comprising water and at least one of blended CO 2 gas bubbles, dissolved H 2 CO 3 , carbonate ions (CO 3 2− ), bicarbonate ions (HCO 3− ), nanosized alkaline earth metal carbonate and nanosized alkali metal carbonate particles. The concrete mixture comprises a cementitious material, aggregates and at least one CO 2 -sequestering chemical for accelerating a CO 2 sequestration speed and maximizing the captured amount of the carbon dioxide.
1. A process for the preparation of a carbonated concrete material, the process comprising the steps of:
mixing a concrete mixture with a CO 2 -containing water to produce a wet concrete mixture;
wherein the concrete mixture comprises a cementitious material and aggregates; and
wherein the CO 2 -containing water comprises CO 2 gas bubbles and at least one of nanosized alkaline earth metal carbonate particles or nanosized alkali metal carbonate particles;
conditioning the wet concrete mixture to produce a ready-to-cure concrete;
allowing the ready-to-cure concrete to harden in curing conditions and produce the carbonated concrete material upon hydration and carbonation of the cementitious material.
2. The process of claim 1 , wherein mixing the concrete mixture with the CO 2 -containing water is performed to add at least 1 kg of CO 2 per m 3 of wet concrete mixture.
3. The process of claim 1 , wherein the cementitious material comprises cement, supplementary cementitious materials (SCMs) or a mixture thereof.
4. The process of claim 3 , wherein the SCMs comprise fly ash, ground granulated blast furnace slag (GGBFS), silica fume, siliceous material, aluminosilicate material, calcined clay, metakaolin, ground glass or any combination thereof.
5. The process of claim 1 , wherein the aggregates comprise concrete sand, gravel, crushed stone or any combinations thereof.
6. The process of claim 1 , wherein the conditioning of the wet concrete mixture comprises at least one of batching, transiting, depositing, forming, consolidating, and finishing the wet concrete mixture.
7. The process of claim 6 , wherein the conditioning comprises transiting the wet concrete mixture, and wherein the transiting is performed in a transit vehicle including a ready-mixed truck.
8. The process of claim 6 , wherein the conditioning comprises depositing the wet concrete mixture, and wherein depositing the wet concrete mixture comprises pouring, conveying, pumping the wet concrete mixture into a curing zone.
9. The process of claim 1 , wherein the mixing is performed in a ready-mixed truck directly at a work site or in a stationary mixer in a plant.
10. The process of claim 1 , wherein the mixing of the concrete mixture with the CO 2 -containing water is performed with a CO 2 -containing water to total cementitious material weight ratio between 0.15 and 2.0.
11. The process of claim 1 , wherein the CO 2 -containing water has a CO 2 to water ratio between 5 g/L and 200 g/L.
12. The process of claim 1 , further comprising dissolving and/or blending carbon dioxide into water to produce the CO 2 -containing water.
13. The process of claim 12 , wherein the water is carried in a feed line at a water flow rate, and dissolving and/or blending carbon dioxide into the water comprises injecting the carbon dioxide into the feed line carrying the water and adjusting the water flow rate and a CO 2 injection speed to deliver at least 1 kg of CO 2 per m 3 of wet concrete mixture.
14. The process of claim 13 , wherein injecting carbon dioxide into the water comprises injecting the carbon dioxide in at least one of a gas phase and a liquid phase.
15. The process of claim 13 , wherein the water flow rate ranges between 300 kg/minute and 1800 kg/minute, and the CO 2 injection flow rate ranges between 1 kg/minute and 40 kg/minute of CO 2 per min.
16. The process of claim 1 , comprising providing the CO 2 -containing water and the concrete mixture in batched amounts to form a pre-mix composition before mixing thereof to produce the wet concrete mixture.
17. The process of claim 1 , wherein the conditioning of the wet concrete mixture comprises batching the wet concrete mixture in a batched amount to form a batched ready-mix composition.
18. The process of claim 1 , wherein the concrete mixture further comprises at least one CO 2 -sequestering chemical that releases species which are ready to be carbonated via the CO 2 -containing water, thereby maximizing hydration and hardening of the cementitious material and maximizing the captured amount of CO 2 in the ready-to-cure concrete.
19. The process of claim 18 , wherein a weight ratio of the at least one CO 2 -sequestering chemical to the cementitious material is between 0.5% and 10%.
20. The process of claim 1 , wherein the concrete mixture comprises at least one CO 2 -sequestering chemical being under the form of ground or fine particles that comprise at least one alkali metal compound, at least one alkaline earth metal compound or a combination thereof, and that generate carbonate particles which densify a concrete microstructure upon carbonation of the at least one CO 2 -sequestering chemical.