Research Project Summary Information
Development & Demonstrations of CO2 Curing Technology for Concrete Products(ST8818-1)
CJS Technology USA, Ltd.
It is common practice to steam cure precast concrete products and masonry blocks after casting. Steam curing is an energy intensive process and represents a significant portion of the product’s cost. The use of carbonation curing could accelerate this process and provide significant energy savings. Several processes have been patented for curing concrete products with carbon dioxide (CO2). However, these processes require using dry concrete mixtures with very low water-to-cement ratios and high compaction pressure for molding products. A process developed by CJS Technology USA, Ltd. allows conventional concrete mixtures with low and medium water-to-cement ratios to be cured with CO2.
Under the project, CJS developed an optimize CO2-curing process under laboratory conditions and tested concrete blocks produced with steam and CO2-curing processes. CJS further conducted long-term performance of concrete blocks cured with CO2 in a laboratory. Concrete paving stone products were also produced and tested with steam- and CO2-curing processes. Additionally, CJS designed a schematic hardware design for implementing the CO2-curing process at a typical existing concrete product manufacturing facility. This work’s results were presented at conferences and published in "Concrete International.
The CO2-curing process takes four to eight hours, compared with 18-24 hours for steam-curing. It is estimated that steam curing consumes about 2500kJ per block of energy (resulting in the release of approximately 0.17 lbs of CO2 equivalent emissions), while only about 500 kJ per block of energy is required and 01.465lbs of CO2 is consumed per black using CO2 curing.
The laboratory curing of full size blocks indicated that carbon dioxide (CO2)-cured blocks have similar compressive strength as steam-cured blocks, and have lower water absorption and drying shrinkage. Both CO2- and steam-cured blocks demonstrated the same behavior during outdoor weathering testing. The whole CO2-curing process could be completed with four to eight hours, compared with 18-24 hours for steam curing. Finally, a CO2-curing process design was proposed and analyzed for use at a block plant. An economic model for estimating the cost of establishing CO2-curing block making operation was developed. This model predicted the per block price premium required for such an operation to create an attractive return on investment.
CJS Technology USA, Ltd.
37 N Union Rd
Williamsville, NY 14221
NYSERDA Contact Information
R&D - Buildings Research