Diatomaceous Earth
Description
Diatomaceous earth is produced by mining areas where diatoms - fossilised remains of aquatic organisms have accumulated over a long period of time. These skeletons contain silica which reacts with oxygen and water to form silicon dioxide making up diatomaceous earth.
The typical chemical composition of oven-dried diatomaceous earth is 80–90% silica, with 2–4% alumina (attributed mostly to clay minerals) and 0.5–2% iron oxide.
Application and Uses
Diatomaceous earth is well known for its multipurpose use including as an insecticide, dietary supplement, stain remover and as a supplementary cementitious material. There are two main types of diatomaceous earth: food grade (consumable) and filter grade (used in the construction industry).
Diatomaceous earth can be used to produce porous lightweight ceramics and in the production of red bricks with higher open porosity. Additionally, it can be used as a partial replacement of portland cement reducing the CO2 emissions released during portland cement production, making it eco-friendly and cost effective. Mix ratios are dependent on the specific job requirements.
Benefits include:
- Better workability
- Increased compressive strength
- Improved resistance to alkali-silica reaction while significantly reducing and refining porosity and improving the resistance to chloride ion penetration.
- Better concrete hydration and curing
- Improved resistance to freeze/thaw cycles
- Improved corrosion resistance
- Better water resistance
- Reduced permeability
- Beneficial coloring/texturing