ABSTRACT
Abstract High-performance concrete has a reputation among field engineers as being more
prone to cracking than conventional concrete. This paper reviews recent research in order to examine whether this is true and how significant cracking is to the durability of reinforced concrete structures. While the results do indicate an increased tendency to cracking in some cases, good concreting practice is effective in mitigating cracking. Silica fume concrete in particular may crack more readily at early ages if not adequately cured. Other results show that cracking need not be deleterious to the service life of a structure provided the concrete is otherwise of high quality. The high electrical resistivity and low permeability and diffusivity of silica fume concrete have beneficial effects on corrosion resistance. In concrete that is continuously submerged, the rate of corrosion is controlled by the availability of oxygen to the cathodic areas of the steel. Thus the thickness and quality of the cover concrete are far more important than the crack width. Keywords: chloride ions, cracking, corrosion, durability, high-performance concrete, silica fume
1 Introduction
Numerous advances in concrete technology in the past few years have led to increases in strength and durability as measured by chloride ion diffusion coefficients in the laboratory. However, there is some question as to whether these improvements can be seen in the field. The measures taken to reduce the rate of deterioration of concrete by reducing its permeability and diffusivity are believed to increase the tendency of the concrete to crack. This paper reviews recent work focusing on three questions: (1) Does high-performance concrete have a greater tendency to crack? (2) If so, how detrimental is cracking to the performance, particularly the durability? and (3) What needs to be done to ensure high performance in the field, not just the laboratory?
