Assessment of reinforcement corrosion in fully carbonated concrete through half-cell potential technique: Investigation of the influence of concrete surface wetting

• Main Author: Bohol, Perlie F.
• Format: text
• Language: English
• Published: Animo Repository 2011
• Subjects: Reinforced concrete—Corrosion; Corrosion and anti-corrosives; Civil Engineering
• Online Access: https://animorepository.dlsu.edu.ph/etd_masteral/7191
• Institution: De La Salle University

Corrosion of reinforcement is one of the major causes of pre-mature deterioration of reinforced concrete structures. In a tropical country like the Philippines, the cyclic wetting and drying climatic condition favors corrosion induced by carbonation. The half-cell potential (HCP) technique is universally used in locating corroding rebars and in assessing the corrosion risk of concrete structures due to its simplicity, cost-effectiveness and rapid diagnosis of corrosion. This study reports the results of half-cell potential measurements obtained on the 31st service life of reinforced concrete columns which are fully carbonated and contaminated with chloride ions. Corrosion predictions from HCP data obtained at four different levels of wetness of concrete surface: (1) dry; (2) minimally wet; (3) thoroughly wet; and (4) after 2 hours drying of thoroughly wet concrete, were compared with the actual corrosion revealed from the direct visual inspection of reinforcements. Results showed that HCP measurement is most effective when performed on minimally wetted concrete surface. At minimally wetted concrete surface condition, 5 out of 9 severely corroded rebars were detected and two of the most corroded columns have been identified through the potential difference technique and statistical evaluation of HCP data, respectively. The HCP technique has been fairly reliable in detecting the most corroded column. But a more reliable corrosion prediction can be attained if HCP technique is complemented with carbonation depth measurements. Another interesting finding of this study is that other than the highest gradient, the lowest gradient in the potential field can also indicate the location of corroding areas on fully carbonated concrete structure.