Thermal cracking of concrete pile caps

Abstract

The large pile caps of buildings and bridges may have superficial cracks already in the early hours after concreting. Due to the large volume of concrete, the temperature inside the pile cap may reach very high values, as a result of the heat of hydration of cement. Because of the strong temperature gradients, the surface of the pile cap is tensioned and may crack. The employment of skin reinforcement does not avoid the cracking of concrete. However, this reinforcement may reduce the crack width, providing the onset of a large number of small cracks, instead of a single crack with large opening. The object of this work is to address this issue by analyzing the main variables involved and suggest a design methodology for the calculation of skin reinforcement of concrete pile caps.