The Performance and Function of Concrete Admixtures

Initially, the use of admixtures was only to save cement. With the development of construction technology, the addition of admixtures has become the main measure to improve the performance of concrete.
Due to the use of high-efficiency water reducing agents, high fluidity concrete, self compacting concrete, and high-strength concrete have been applied; Due to the presence of thickeners, the performance of underwater concrete has been improved: due to the presence of retarders, the setting time of cement has been extended, making it possible to reduce slump loss and prolong construction operation time; due to the presence of antifreeze, the freezing point of the solution has been lowered, or the deformation of the ice crystal structure has not caused frost damage Construction can only be carried out under negative temperature conditions.
Overall, admixtures have the following effects in improving the performance of concrete:
(1) It can reduce the water consumption of concrete Alternatively, the flowability of concrete can be increased without increasing the water usage.
(2) The setting time of concrete can be adjusted.
(3) Reduce bleeding and segregation Improve workability and resistance to water washing.
(4) It can reduce slump loss Increase the pumpability of pumped concrete.
(5) It can reduce shrinkage Adding expansion agent can also compensate for shrinkage.
(6) Delay the initial hydration heat of concrete Reduce the temperature rise rate of large volume concrete and minimize the occurrence of cracks.
(7) Improve the early strength of concrete Prevent freezing at negative temperatures.
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2022 Construction Practice Enhancement Class 08
(8) Improve strength, enhance frost resistance, impermeability, wear resistance, and corrosion resistance.