The presence of water is a basic requirement for the development of high-strength concrete. The cement itself does not have any adhesive properties. However, the reaction of cement and water produces a composite calcium silicate hydrate [better known as CSH gel] which is the best binder.
The water used in concrete should be free of any impurities and should be portable, clean and suitable for drinking. The presence of acidic and basic salts can affect the strength of the concrete. However, if there is nothing that can be used to make clean water, seawater can also be used in consideration of the loss of strength caused by the former.
The presence of water gives the concrete a natural flow, making it easier to use and apply to the masonry surface.
The water-cement ratio is a fundamental feature of ready-mixed concrete design; masons develop a bad habit of increasing the proportion of water in the cement compared to standards that improve processability and make it easier to transport, handle, mix, place and integrate. However, according to the inverse relationship between the water-cement ratio and the concrete strength given by Abraham, the excess water content reduces the compressive strength of the concrete.
The large use of water is in the curing of concrete. Curing is the process of bringing concrete into contact with water for at least seven days to achieve its ultimate strength. Because of its high specific gravity, water can dissipate heat from the concrete surface and help prevent thermal cracking due to excess heat generated during the hydration process. The tests performed by the quality control unit included testing the compressive strength of the 150 mm concrete cubes stored in the vulcanization tank for 3, 7, 14 and 28 days, respectively. A similar test procedure for bending strength involves curing the compact in water and determining its strength.
Concrete is very strong in compression, but it is weak in tension, so the tensile strength is negligible. However, tests are recommended to calculate the required compliance below the neutral axis in areas subject to high tensile stress and in the development of prestressed concrete. For new structures, by placing Brussels and jute bags on columns and stairs and closing a water-filled area to solidify the roof, the surface remains wet for several days, which slowly releases heat from the structure and facilitates the development of any crack study. Through experiments, it was found that steam curing is the best form of the ultimate strength of solidified concrete.
The above factors prove the importance of water in concrete.
Orignal From: The importance of water in concrete
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