The role of cement concrete admixtures

The initial use of concrete admixtures was just to save cement. With the development of construction technology, the use of concrete admixtures has become the main measure to improve the performance of concrete.
Thanks to the high-efficiency water-reducing agent, high-fluidity concrete, self-compacting concrete, and high-strength concrete have been applied; thanks to the thickening agent, the performance of underwater concrete has been improved; thanks to the retarder, the setting time of cement has been extended , it is possible to reduce the slump loss and extend the construction operation time: due to the antifreeze, the freezing point of the solution can be lowered, or the deformation of the ice crystal structure will not cause freezing damage. Only then can construction be carried out at negative temperatures.
Generally speaking, concrete admixtures have the following effects in improving the performance of concrete:
(1) It can reduce the water consumption of concrete. Or it can increase the fluidity of concrete without increasing water consumption.
(2) The setting time of concrete can be adjusted.
(3) Reduce bleeding and segregation. Improve workability and water elution resistance.
(4) It can reduce slump loss and 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 reduce the occurrence of cracks.
(7) Improve the early strength of concrete and prevent freezing at negative temperatures.
(8) Improve strength, increase frost resistance, impermeability, wear resistance, and corrosion resistance.
(9) Control the alkali-aggregate reaction. Prevent the corrosion of steel bars and reduce the diffusion of chloride ions.
(10) Made into concrete with other special properties.
(11) Reduce the viscosity coefficient of concrete, etc. </p