Long term correlation between concrete cracking and corrosion in natural marine micro-environments

Concrete cracking due to corrosion of the reinforcing steel has been widely studied since the 70´s of the last century. Efforts have also been made to predict remaining service life based on available results of concrete cracking from accelerated corrosion procedures. Although accelerated experiments have been an important tool for this task, natural environment results are still needed to validate findings. A long-term correlation between concrete cracking and corrosion from two natural marine micro-environments is presented in this investigation. As expected, water/cement (w/c) ratio was the relevant variable for concrete performance in the two tropical micro-environments. An experimental correlation for natural corrosion between visible appearance of cracks at the surface of concrete (CWMAX) and loss of metal (XAVER) of naturally exposed reinforced concrete cylinders with r0 as nominal diameter of reinforcing bar: CWMAX ~ 18.4 xAVER/r0 was found. In addition, an empirical correlation was obtained from metal XAVER and maximum pit depths (PITMAX): PITMAX ~ 9.2 XAVER, corroborating empirical calculations form previous investigations with estimates of PITMAX ~ 10 XAVER.