Non-uniform distribution of rust layer around steel bar in concrete

The thickness of rusted layers at steel/concrete interface from a chloride-exposed reinforced concrete specimen was observed by digital microscopy. The non-uniform corrosion front is presented by a Gaussian function, the parameters in the model, including the non-uniformity coefficient, the spread coefficient, and the uniformity coefficient, are studied to describe the non-uniform distribute characters of rust layer. Comparing with the models proposed by other researchers, the Gaussian model can describe the non-uniform rust layer better. The location of corrosion peak along the perimeter of rebar and the condition for corrosion spreading across the entire circumference of rebar are discussed. (C) 2011 Elsevier Ltd. All rights reserved.