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Admixture

Concrete admixture

  • A material other than water, aggregates, or cement that is used as an ingredient of concrete or mortar to control setting and early hardening, workability, or to provide additional cementing properties. Over decades, attempts have been made to obtain concrete with certain desired characteristics such as high compressive strength, high workability, and high performance and durability parameters to meet the requirement of complexity of modern structures. The properties commonly modified are the heat of hydration, accelerate or retard setting time, workability, water reduction, dispersion and air-entrainment, impermeability and durability factors.
    ​Type of admixture
    Chemical admixtures
    Mineral admixtures
    Chemical admixtures
  •  Water-reducing admixture / Plasticizers
  • 1.    To achieve a higher strength by decreasing the water cement ratio at the same workability as an admixture free mix.
    2.    To achieve the same workability by decreasing the cement content so as to reduce the heat of hydration in mass concrete.
    3.    To increase the workability so as to ease placing in accessible location
  •  Super Plasticizers
    1.    Increased fluidity
    2.    Reduced W/C ratio
  • Accelerators
    1.    Set Accelerating Admixtures
    2.    Hardening Accelerators
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  • Set Retarders
    The function of retarder is to delay or extend the setting time of cement paste in concrete. These are helpful for concrete that has to be transported to long distance, and helpful in placing the concrete at high temperatures.
  • Air Entrained Admixtures
    An addition for hydraulic cement or an admixture for concrete or mortar which causes air, usually in small quantity, to be incorporated in the form of minute bubbles in the concrete or mortar during mixing, usually to increase its workability and frost resistance. Air-entraining admixtures are surfactants that change the surface tension of the water. Traditionally, they were based on fatty acid salts or vinsol resin but these have largely been replaced by synthetic surfactants or blends of surfactants to give improved stability and void characteristics to the entrained air. Air entrainment is used to produce a number of effects in both the plastic and the hardened concrete.