• Construction Concrete Admixture Other Additives

STMP (Sodium Trimetaphosphate)

• STMP (Sodium Trimetaphosphate) is sometimes used as a concrete admixture additive that can provide a range of benefits to concrete, including improved strength, workability, and durability. These benefits are due to the chemical mechanism by which phosphate ions in the STMP solution interact with the concrete’s cement particles and hydration products.

  STMP use as a concrete admixture additive can be explained as follows:

  • Water reduction: STMP can act as a water-reducing agent in concrete mixes. This is because the phosphates in the STMP solution can coat the surface of the cement particles, thereby reducing the electrostatic attraction between the particles and allowing water to penetrate more easily. As a result, less water is needed to achieve the same workability and strength, leading to denser and stronger concrete.
  • Improved workability: STMP can improve the workability of concrete by increasing the fluidity of the mix. This is because the phosphate ions in the STMP solution can act as a lubricant between the cement particles, thereby reducing the friction and facilitating the better flow of the mix.
  • Increased strength: STMP can also increase the strength of concrete by promoting the formation of Calcium Silicate Hydrates (CSH) and reducing the amount of un-hydrated cement in the mix. This is because the phosphate ions in the STMP solution can react with the calcium ions in the cement to form insoluble calcium phosphate compounds, which in turn can promote the formation of CSH and reduce the amount of un-hydrated cement.
  • Improved durability: STMP can enhance concrete’s durability by reducing the mix’s permeability. This is because the phosphate ions in the STMP solution can react with the calcium ions in the cement to form insoluble calcium phosphate compounds, which can help to fill the voids and cracks in the concrete and reduce the permeability.
  • Cost-effectiveness: STMP is a relatively inexpensive additive that can be easily incorporated into concrete mixes. This can lead to cost savings in concrete production, particularly in large-scale construction projects.

  References:

  • Shi, C., & Wu, Z. (2005). Effect of sodium tripolyphosphate on the performance of concrete. Cement and Concrete Research, 35(8), 1572-1575.
  • Kaviya, K. S., & Deepa, K. (2019). An experimental study on the influence of Sodium Trimetaphosphate (STMP) on the properties of concrete. International Journal of Civil Engineering and Technology, 10(2), 1728-1735.