Corrosion-induced cracking of the concrete cover

Background

Precipitation of corrosion products in the concrete pores may give rise to expansive stresses and lead to concrete cracking and spalling. Cracks are undesirable for numerous reasons, e.g. because they promote further ingress of species that may trigger additional deterioration mechanisms.

The conceptual understanding forming the state-of-the-art for modeling corrosion-induced concrete cracking is from a rather global perspective and does not address the fundamental processes in sufficient detail. Most existing models are empirical and calibrated with accelerated laboratory testing. The predictive power of these models has been shown to be poor.

Aims and objectives

The aim was to establish mechanistic descriptions of transport and precipitation of corrosion products in the concrete pore system, and by taking into account the dual thermodynamic and poromechanical nature of expansive stresses generated by precipitated corrosion products in concrete. This will pave the way for a new generation of crack-prediction models.

Methodology

The methodology involved a combination of numerical modeling and experimental measurements. We used modern experimental techniques to characterize the pore structure of the concrete. Recent advances in poromechanics have laid the basis for predicting damage caused by expansive pressure arising from precipitation of compounds in pores. In this project, we have combined this new knowledge with established methods of modeling mass transport in concrete constitutes