Rice Husk Ash (RHA)

RHA, or rice husk ash, has two functions in concrete building. In order to lower the cost of concrete, rice husk is first used as a Portland cement substitute. It also serves as an admixture in the creation of high strength concrete.
It should be noted that the kind of rice husk ash utilized in concrete is amorphous rather than crystalline, making it appropriate for pozzolanic activity.
In the construction industry, rice husk ash finds numerous uses, including in roofing shingles, high-performance concrete, insulation, green concrete, bathroom flooring, industrial manufacturing flooring, waterproofing, and restoration.

Utilizing Rice Husk Ash in Construction Projects

1. Affordable Building Components

There is a great need for inexpensive building materials because ordinary Portland cement is pricey in developing nations. Since cement is the most expensive component of concrete, adding rice husk ash in place of some of the cement would significantly reduce the cost of the finished product.
It has been shown that adding rice husk ash in place of 50% of the cement might cut the price of concrete by 25%. To manufacture blocks, an Indonesian company mixed a mixture of 10% cement, 50% aggregate, 40% RHA, and water. The blocks had an average strength of 12 MPa

2. Bricks used in refractory construction

Because rice husk ash has good insulating qualities, it has been used to make refractory bricks. In refractory bricks, where the organic matter is burned away during the firing process to create a lightweight porous product, it can be utilized as an organic filler. Furnaces that are subjected to high temperatures are equipped with refractory bricks

3. Materials for Lightweight Construction

The production of lighter goods, such as hollow blocks with improved thermal insulation qualities that provide lighter walls for steel-framed buildings, is made possible by higher strength concrete with RHA.
Additionally, less cement and aggregate are used. Using rice husk ash, lightweight insulating boards are made.

4. Material for Insulation

It is utilized in homes, farms, and cold storage facilities as a loose insulator. They can be flameproofed if desired by soaking in a boric acid and borax solution. The ability of rice hulls to insulate is fairly good.

5. Soil Enhancement

For superficial stability, a tiny amount of cement mixed with rice husk ash might be utilized.

6. The Steel Sector

The steel industry uses rice husk ash to make premium flat steel. Because of its desired properties, which include low bulk density, high porosity, high melting point, and low thermal conductivity, rice husk ash is utilized as an insulator.
It is employed to guarantee homogeneous solidification and stop the steel from cooling down too quickly. However, because rice husk ash oxides with steel’s constituent elements, including aluminum, to generate alumina (Al2O3), there are health concerns associated with using it in the manufacturing of steel.