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Example of flat piece of concrete having dislodged with corroded rebar underneath, Welland River bridge across Queen Elizabeth Way in Niagara Falls, Ontario. The expansion of the corrosion products (iron oxides) of carbon steel reinforcement structures may induce internal mechanical stress (tensile stress) that cause the formation of cracks and disrupt the concrete structure.
The 2023 United Kingdom reinforced autoclaved aerated concrete crisis relates to increased safety concerns over reinforced autoclaved aerated concrete, commonly used historically in roofing and wall construction within the public sector, having gained popularity in the mid-1950s as a cheaper and more lightweight alternative to conventional reinforced concrete.
Concrete cancer may refer to: . Rebar corrosion and spalling of the concrete cover above rebar caused by the rust expansion and accelerated by chloride attack and pitting corrosion of the steel reinforcements.
Initiation and propagation periods of steel rebar corrosion in a reinforced concrete structure (Tutti diagram). [2] [3] Initially, the chemical reactions that normally occur in the cement paste, generate an alkaline environment, bringing the solution in the cement paste pores to pH values around 13. In these conditions, passivation of steel ...
Dowel bar retrofits, if done badly, can cause serious problems. These problems are usually due to poor workmanship and can be avoided by careful following of specifications and close supervision of workers. Use of heavy jackhammers (heavier than 14 kg class) tends to cause cracking of the concrete all around the slots.
In order to minimize the effect, placing the electrodes above a rebar is usually avoided, or if unavoidable, then they are placed perpendicular to the rebar. However, measurement of the resistance between a rebar and a single probe at the concrete surface is sometimes done in conjunction with electrochemical measurements.
When a concrete structure is designed, it is usual to specify the concrete cover for the rebar (the depth of the rebar within the object). The minimum concrete cover is normally regulated by design or building codes. If the reinforcement is too close to the surface, early failure due to corrosion may occur.
Crosshole sonic logging (CSL) is a method to determine the structural integrity of drilled shafts and other concrete piles.. The CSL method is considered to be more accurate than sonic echo testing in the determination of structural soundness of concrete within the drilled shaft inside of the rebar cage.