Investigation of Effects of Different Environmental Conditions on Balance Time of Bleeding and Evaporation in Plastic Shrinkage of Concrete Pavements

One of the causes of early-age cracking in concrete pavements is plastic shrinkage. This shrinkage occurs after the balance of bleeding and evaporation and the formation of negative capillary pressures at the pavement surface. Different environmental conditions cause the rate of evaporation to change, resulting in a change in time of balance and subsequent cracking. This study, using the standard ASTM C 1579 method, examined the relationship between time of balance of bleeding and evaporation, and cracking area in concrete in 27 different environmental conditions, including a combination of three ambient temperatures, three wind speeds, and three relative humidities with using a continuous video recording system and digital image analysis. The results showed that there was a significant relationship between time of balance and severity of plastic shrinkage cracking. By reducing the time of balance from the maximum value to its minimum value, the cracking area increased by more than four times. It was seen that the combination of environmental conditions has a significant effect on increasing or decreasing the severity of cracking, and the fact that only one factor is critical cannot necessarily create critical conditions for plastic shrinkage cracking. Time of balance can be an essential factor in controlling and reducing plastic shrinkage cracking and assessing the effects of different environmental conditions on the severity of cracking in concrete pavements. It is necessary to control this factor during the construction of concrete pavements in different environmental conditions.