FR2121975A5 - Carbon dioxide treatment of concrete - using a single reaction zone for initial setting, conditioning gas absorption and cooling - Google Patents

Abstract

Treatment of concrete blocks with CO2 at normal pressures, in the following stages:- setting of the newly made block, conditioning of the concrete by hydration, treatment with CO2 and cooling, in which the blocks are treated continuously to the required extent in each stage, the special features of the process being that: (a) all stages of treatment are carried in the atmosphere provided within a single reaction zone, (b) setting is brought about by addition of excess steam to bring the humidity in the zone to a high value, which is maintained to bring about the conditioning of the blocks until their temp. exceeds that of the atm. in the zone, while the CO2 content of the zone is suddenly increased. (c) treating the blocks by cutting off the steam injection and injecting CO2 and supplying heat to the zone in response to >=1 of the above parameters, and thus causing an increase in the temp. of the zone corresponding approx. to that of the blocks, while bringing about the decrease of the CO2 content and humidity in the atm. of the zone to values which remain practically constant for the remainder of the treatment, (d) cooling the blocks while reducing the amount of CO2 and heat supplied to the zone, in response to the completion of the treatment of the blocks, (e) withdrawal of the blocks from the treatment zone at 60 degrees C.