Durability of Reinforced Concrete Structures, Theory vs Practice

SCCT Durability of Reinforced Concrete Structures, Theory vs Practice Albert K.H. Kwan and Henry H.C. Wong Department of Civil Engineering, The University of Hong Kong, Hong Kong Abstract: The durability of concrete as a construction material and the durability of reinforced concrete structures under different environmental conditions are probably the least understood attributes of concrete. No simple theory applies and only incremental advancement based on experiences gained through practice can be achieved. This paper addresses this issue, with particular emphasis on the possible improvement of durability through better concrete mix design (or more specifically use of high-performance concrete), more careful crack control, use of corrosion inhibitors and use of protective coatings. 1. Introduction The durability of a structure is its ability to serve its intended purposes for a sufficiently long period of time, or at least during its expected service life. However, although a durable structure is expected to serve without deterioration to the extent that major repair is required before expiry of its design life, it must not be presumed that durability is a substitution for good maintenance. Even for a structure that has been designed and constructed to a high durability standard, regular inspection and routine maintenance to restore the fitness for purpose of the structure are needed. Hence, when we come to the durability design of a structure, we must bear in mind the future need for maintenance and take into account the cost of maintenance in the life cycle cost analysis of the structure. A reinforced concrete structure may deteriorate because of deterioration of the concrete itself or because of corrosion of the steel reinforcing bars inside the concrete. Common causes of the deterioration of concrete include alkali-aggregate reaction, chemical attack, freezing and thawing action, abrasion and fire. There is often the misunderstanding that carbonation and chloride attack would cause deterioration of concrete. In actual fact, carbonation and chloride attack would not cause any harm to 1

Durability of Reinforced Concrete Structures, Theory vs Practice

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