Introduction. The article considers the fundamental problem of ensuring the durability of highway bridges under aggressive chloride action. The operational reliability of transport structures is largely determined by the condition of reinforced concrete structures exposed to de-icing agents and cyclic wetting.
Problem Statement. Chloride-induced corrosion of reinforcement is one of the most dangerous degradation factors, leading to a loss of load-bearing capacity and premature failure of bridges. The existing regulatory framework of Ukraine only partially accounts for these processes, necessitating harmonization with international standards.
Objective. The objective of this work is to systematize theoretical knowledge regarding chloride mass transport mechanisms, analyze the influence of mineral admixtures and carbonation on corrosion resistance, and review modern regulatory methods for determining chloride content to improve the national bridge monitoring system.
Materials and Methods. Methods of analytical review of scientific literature and regulatory documents regarding diffusion processes, thermodynamic modeling of chloride binding, and probabilistic risk assessment methods were used.
Results. The differences between free and bound forms of chlorides are analyzed, and the effect of carbonation on the release of bound salts is examined. Regulatory methodologies for determining water- and acid-soluble chlorides, their advantages, and limitations are described in detail. The necessity of transitioning from deterministic threshold values to probabilistic models of corrosion risk assessment is substantiated.
Conclusions. The results demonstrate effective durability prediction of transport structures requires differentiated consideration of free and bound chlorides, especially for concretes with mineral admixtures and under carbonation conditions. The feasibility of implementing ASTM C876 and AASHTO T 260 methodologies into domestic bridge monitoring practice is substantiated. The proposed approach allows for the identification of corrosion processes at the initiation stage, which is a prerequisite for introducing asset management systems based on actual technical condition.
