A method of applying carbon dioxide to concrete during the production of the concrete, the method comprising: determining if there is sufficient carbon dioxide in a storage container; after determining there is sufficient carbon dioxide in the storage container, starting a mixer; placing a predetermined amount of concrete materials in a mixing chamber of the mixer, wherein the mixing chamber has an aperture; determining if an injection assembly is in a position to inject carbon dioxide into the mixing chamber of the mixer, wherein the injection assembly is in fluid communication with the storage container by piping interconnected to the storage container, a control valve (10, 20, 56), a liquid gas separator, and the injection assembly; after determining the injection assembly is in the position to inject carbon dioxide into the mixing chamber, moving the control valve (10, 20, 56) to an open configuration to allow liquid carbon dioxide to leave the storage container and enter the piping; separating gaseous carbon dioxide from liquid carbon dioxide in the piping by the liquid-gas separator, wherein gaseous carbon dioxide is released from the piping through a vent to the atmosphere, and wherein liquid carbon dioxide continues through the piping to the injection assembly; injecting carbon dioxide into the mixing chamber of the mixer by the injection assembly, wherein the injection assembly is operable to cause liquid carbon dioxide to change state to a mixture of solid carbon dioxide and gaseous carbon dioxide; determining that a predetermined amount of carbon dioxide has been injected into the mixing chamber of the mixer; after determining that the predetermined amount of carbon dioxide has been injected into the mixing chamber, moving the control valve (10, 20, 56) to a closed configuration to prevent liquid carbon dioxide from leaving the storage container; mixing the concrete materials and the carbon dioxide until a chemical reaction between the concrete materials and the carbon dioxide is complete; and discharging the concrete from the mixing chamber of the mixer; wherein the injection assembly injects between 0.6 and 16 kg of carbon dioxide into the mixer for each cubic metre of concrete mix in the mixer. determining if there is sufficient carbon dioxide in a storage container; after determining there is sufficient carbon dioxide in the storage container, starting a mixer; placing a predetermined amount of concrete materials in a mixing chamber of the mixer, wherein the mixing chamber has an aperture; determining if an injection assembly is in a position to inject carbon dioxide into the mixing chamber of the mixer, wherein the injection assembly is in fluid communication with the storage container by piping interconnected to the storage container, a control valve (10, 20, 56), a liquid gas separator, and the injection assembly; after determining the injection assembly is in the position to inject carbon dioxide into the mixing chamber, moving the control valve (10, 20, 56) to an open configuration to allow liquid carbon dioxide to leave the storage container and enter the piping; separating gaseous carbon dioxide from liquid carbon dioxide in the piping by the liquid-gas separator, wherein gaseous carbon dioxide is released from the piping through a vent to the atmosphere, and wherein liquid carbon dioxide continues through the piping to the injection assembly; injecting carbon dioxide into the mixing chamber of the mixer by the injection assembly, wherein the injection assembly is operable to cause liquid carbon dioxide to change state to a mixture of solid carbon dioxide and gaseous carbon dioxide; determining that a predetermined amount of carbon dioxide has been injected into the mixing chamber of the mixer; after determining that the predetermined amount of carbon dioxide has been injected into the mixing chamber, moving the control valve (10, 20, 56) to a closed configuration to prevent liquid carbon dioxide from leaving the storage container; mixing the concrete materials and the carbon dioxide until a chemical reaction between the concrete materials and the carbon dioxide is complete; and discharging the concrete from the mixing chamber of the mixer; wherein the injection assembly injects between 0.6 and 16 kg of carbon dioxide into the mixer for each cubic metre of concrete mix in the mixer.