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.

► The thickness of rust layer deposited on the circumference of a steel bar in concrete is presented by a Gaussian function. ► The parameters in the Gaussian model can describe the non-uniform distribute characters of rust layer. ► Steel corrosion spreading across the entire circumference of rebar happens after concrete surface cracking.