Generally, mixing cement and gypsum is usually unfeasible and not recommended for construction purposes.
While both cement and gypsum are building materials, their chemical interaction when mixed can lead to serious problems, compromising the integrity and durability of the resulting material.
Why Mixing Cement and Gypsum is Problematic
The primary reason mixing Portland cement and gypsum is unfeasible is the detrimental chemical reactions that occur. The reference states that these reactions lead to the formation of specific expansive compounds.
- Formation of Ettringite: When gypsum is present as a minor component in the blend with Portland cement, it can react to form ettringite.
- Formation of Thaumasite: If gypsum is a major component in the mixture, the reaction can lead to the formation of thaumasite.
Both ettringite and thaumasite are crystalline compounds that cause significant expansion within the hardened material. This internal expansion creates stress, leading to:
- Cracking: The material expands beyond its capacity, causing fissures and cracks.
- Deterioration: The structural integrity is severely weakened over time.
These issues make the mixed material unsuitable for most applications where stability and long-term performance are required.
In summary, the chemical incompatibility between cement and gypsum results in damaging expansive reactions, making their direct mixture typically unfeasible for reliable construction.
