The invention encompasses equipment used to condition a recirculating gas stream in order to cure a CO2 Composite Material (CCM) and processes that use such equipment to cure the CCM. The gas conditioning equipment allows for a process that controls, reduces or eliminates the rate-limiting steps associated with water removal during the curing of a composite material. The equipment may include, but will not be limited to, control over the temperature, relative humidity, flow rate, pressure, and carbon dioxide concentration within the system; which includes the conditioning equipment, any vessel containing the CCM, and the material itself. Flow rate control can be used as a means to achieve uniformity in both gas velocity and composition.