In order to determine the limit of time interval for placing concrete on consolidated fresh concrete to prevent cold joints, which impair water tightness and durability of concrete structures, laboratory experiments were conducted on the durability between lower and upper layers. Concrete mixtures with ordinary portland cement and eco-cement were tested for accelerated carbonation on specimens with the time intervals up to 6 hours for placing upper concrete on consolidated lower concrete. The test results indicated that the depth of carbonation of the ordinary portland cement was deeper than the eco-cement, and carbonation of concrete joints were faster and deeper than the ordinary placed concrete.
