concrete
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Cavitation effect in concrete
Cavitation is a physical process that leads to surface pitting caused by the collapse of vapour bubbles, which results in a sudden rise in local pressure. In this article, we explore how this phenomenon can damage concrete. Damages by cavitation Cavitation can damage the concrete in the following ways: Shock Waves Generated by Bubble Implosion:…
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Durability of concrete in terms of water permeability
Permeability is one of the main indicator defining the durability of the concrete. In one hand, the permeability of the concrete can be high from the beginning of concrete life, in which case, the deterioration takes place rapidly during the service life. While in the other hand, the permeability of the concrete may gradually increase…
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Degradation of concrete by abrasion
Abrasion of concrete is progressive loss of concrete mass due to mechanical degradation such as friction, grinding action, impact, overloading and local crushing. Vehicular movement and pedestrian traffic causes abrasion. The worst effect of abrasion is caused by vehicle with studded/chain tyres. Similarly, in industrial buildings, the concrete floors are subjected to impact load and…
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Using microbes for durable concrete
Conventionally, organic matters in concrete were considered to be undesirable. But recent study with selected microbes has shed new light on its usefulness. Both useful and deteriorating microbes has been identified. Metabolic activity of microbes produces acid which degrade concrete. These kinds of deterioration are pronounced in location having high microbial activities such as near…
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Leaching in water retaining structures
Cement requires water to undergo hydration. However, after hydration is complete, excess water can dissolve the hydration products, causing leaching and weakening the structure. This issue is particularly critical for water-retaining concrete structures. For example, in dams, hydrostatic pressure and water permeability can cause the rapid leaching of these hydration products. This article examines the…
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Leaching and Efflorescence of concrete
In structures such as dam where the flow of water via pores of concrete is high, there could be significant loss of mono-sulfate and ettringite and decalcification of calcium silicate hydrate due to leaching out of these salts to the surface and subsequently washing away. This will lead to reduction in strength of concrete and…
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Health of reinforced concrete structure based on construction quality
Reinforced concrete (RC) structures exhibit significant variability during construction, primarily due to the in-situ casting process. This method introduces numerous factors that can affect quality. As Richard Feynman wisely noted, “The first principle is that you must not fool yourself—and you are the easiest person to fool.” This insight is particularly relevant in the construction…
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Impact of bad formwork of concrete in its service life
Formwork plays a vital role in reinforced concrete (RC) design, providing support for the concrete until it gains adequate strength. Its complexity can range from simple cubic boxes to intricate spline surfaces. While formwork design is a specialized area of concrete engineering, this article focuses on how poor formwork affects the service life of RC…
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Pull out test in concrete
The bond between concrete and steel is a crucial factor in structural integrity. As concrete ages, this bond often weakens. This article outlines the procedure for conducting a pull-out test to evaluate bond strength. In tests with plain rebars, the maximum load typically coincides with the moment of initial slip. In contrast, deformed bars can…