【正文】 0. [2] Alekseyev SN, Rozental NK. Resistance of reinforced concrete in industrial environment (in Russian). Strogisdat, Moscow: 1976. [3] Bentur A, Diamond S, Berke NS. Steel corrosion in amp。48(3):154–62. [10] Ramachandran VS, editor. Properties, science and admixtures handbook. Noyes Publication。(September/October):10–3. [6] Moskvin VM, Alexev SN. Beton i Zhelezobeton 1957。 Reinforcement 1. Introduction It is an unfortunate fact that very large amounts of existing concrete structures worldwide are in a state of eterioration/distress. At the same time, it must also be recognized that many repaired concrete structures are severely deteriorated only a few years after being repaired. The performance of repaired concrete structures remains a matter of utmost concern to all those involved with their design, construction, maintenance and use. Few problems aggravate the public and lead to their dissatisfaction with our ability to 6 provide for the structures use than the disruption of its use a few years after repairs. Contrary to the expectations, the problem of corrosion in concrete repairs has bee widespread not only with respect to severe environmental conditions but also with respect to moderate environmental condition. The concrete repair industry is thus facing a major challenge: How to halt the decay of the world’s physical infrastructure. It is therefore important that we critically examine the issue of corrosion and corrosion protection in today’s concrete repair and explore how it can be improved in the near future, .: how to make today’s repairs durable for tomorrow. A basic understanding of the processes leading to premature corrosion in repaired structures still eludes the concrete repair munity. This applies not only to the processes of corrosion of reinforcement in repaired structures and deterioration/ distress of concrete, but also to a variety of the proposed solutions––corrosion protection techniques, materials and systems. They have a highly empirical history of use, and their performance in many cases is questionable. This paper offers some random thoughts in the area of reinforcement corrosion and protection in concrete repair. It enpasses the elucidation of the basic processes of corrosion of steel in repair, electrochemical inpatibility, and how these processes may lead to eventual failure of the posite repair system. The paper is also about how we can, or cannot, successfully address these problems with the aim of prolonging lifetime of existing concrete structures. After all, we must pause periodically from our busy schedules to review where we are and where we might be going. Of course, there are some thoughts in this paper which may lead others to agree or disagree. But it is only when ideas receive a forum that progress can be made, and that is the goal of this paper. It is not possible here to provide a critical review of numerous aspects of corrosion and corrosion protection, the problems are too extensive and various mechanisms too plicated for a critical discussion in a single paper. General aspects of steel corrosion in concrete and its protection have been treated by a number of authors and will not be addressed here. Research has substantially improved our knowledge of cementitious materials, the fundamentals of concrete deterioration from carbonationinduced corrosion, chlorideinduced corrosion, sulphate attack, alkali–aggregate reaction, frost, etc. However, in view of the serious and 7 insidious nature of the corrosion of steel in concrete repair and repair failures, it is surprising that progress in the repair industry has been so slow, which is probably attributable to some bination of the following: the exterior and interior environments and their interaction. problems does not exist. The mechanism of passivation and corrosion of steel in a plex repair environment is poorly understood. The whole area concerning “additional protection” of reinforcement in repair is currently highly speculative. is an extremely plex phenomenon involving environmental, metallurgical, interfacial, and continuum considerations. Most of the research in this area is being done by the civil engineering departments of universities where few workers have adequate knowledge of the subject. in support of research leading to a resolution to problems. Real progress cannot be made on the basis of graduate students working for limited periods. It is necessary to initiate programs which include a balanced practical approach and are adequately funded. by using high performance materials, corrosion inhibitors, protective coatings, etc., or belt and suspender systems. This caused many workers in the field to ignore the basics in the technology of concrete and other cementbased materials. ficant knowledge to design durable repairs already exists in a relatively “quite refined state”, as stated by Mather [1]. But the manner in which this knowledge is used is primitive. Several research studies in the repair field have been concerned with the improvement of properties of repair materials and their dimensional behaviour relative to the existing substrate. But these activities will lead to improvements in repair durability only if the issues of electrochemical patibility are also addressed. Removal of deteriorated concrete and its replacement with a repair material, even the best one, may result in accelerated rebar corrosion due to macrocell formation. The subject of this paper is also devoted to several con