Size distribution model and development characteristics of corrosion pits in concrete under two curing methods

Abstract

In this paper, the effect of chloride ions on the development of corrosion pits in different reinforced concrete under different environmental conditions is studied. A fitting model for the size distribution of pits in seawater and sea-sand concrete (SSC) under different curing modes is established, and time-dependent fractal features are examined. Under wet/dry chloride cycles, the weight loss rate and corrosion rate of steel bars are higher, and the number of corrosion pits appears to increase on a small scale within 60-day. A majority of the corrosion is metastable pitting, and we propose a model to describe the size distribution of pitting in different periods. The good agreement between the proposed model and the available data illustrates that the proposed model is reliable and accurate. Macroscopic pitting occurs first in wet/dry chloride cycles. With the increase of concrete age, the size distribution of pits under wet/dry chloride cycles is uneven, and the pit sizes in submerged concrete tend to be equal.