• Construction Concrete Admixture Defoamers

TBP (Tributyl Phosphate)

• TBP is commonly used in concrete mixtures to prevent the formation of excessive foam or bubbles during the mixing process.

  TBP is an organic phosphate soluble in various solvents, including water—typically added to the concrete mix during the mixing process, either as part of a pre-mixed admixture or as a separate additive. The dosage rate of these additives varies depending on the specific application but is generally between 0.1% to 1% by weight of cement.

  The mechanism by which TBP works to reduce foam and bubbles in concrete involves their ability to reduce the surface tension of the concrete mixture. When these additives are added to the mix, they reduce the surface tension of the water and air within the mix, which helps to break down the bubbles and prevent them from forming. This is achieved by the organic phosphate molecules in the additive adsorbing onto the surface of the air bubbles, which reduces the energy required to break the surface tension and merge the bubbles.

  In addition to reducing surface tension, TBP also acts as a defoaming agent by destabilizing foam. This lowers the interfacial pressure between the liquid and gas phases, which promotes the coalescence of foam bubbles and destabilizes the foam structure.