Risk of Pavement Fracture due to Eigenstresses at Early Ages and Beyond

Abstract

Tensile cracks significantly affect the durability of concrete pavements, leading to an increase in the costs of maintenance and rehabilitation. A model is developed that relates thermal, chemical, and hygral evolutions at small scales due to different distress mechanisms to the risk of fracture at the structural scale. The method is based on application of linear elastic fracture mechanics (LEFM) to eigenstresses that develop in infinite- and finite-length beams on an elastic foundation that represents the subgrade. Axial and bending contributions to the energy release rate are determined for a worst-case scenario of an entirely cracked pavement section in functions of material properties, structural dimensions, and eigenstress forces and moments. By way of example, the model is used to study the risk of fracture of concrete pavements due to two different mechanisms: (1) autogeneous shrinkage at early ages of placing the concrete and (2) thermal cycles at the short term and long term after a temperature change. In addition, scaling relationships are developed that provide insight into the improvement of different structural and material properties for minimizing the risk of fracture.