Carbon-Negative Construction Material Based on Rice Production Residues.

Area of Science:

• Materials Science
• Sustainable Construction
• Waste Valorization

Background:

• Agricultural wastes such as rice husk ash, wood ash, and rice straw pose disposal challenges in many African regions.
• Portland cement production is a major contributor to global anthropogenic CO2 emissions.
• There is a need for cost-effective, sustainable building materials for affordable housing.

Purpose of the Study:

• To develop a cost-effective, carbon-negative construction material from locally available agricultural wastes.
• To evaluate the suitability of this composite for affordable housing applications.
• To investigate the potential for reducing CO2 emissions in the construction sector.

Main Methods:

• Utilizing rice husk ash (high amorphous silica) as a pozzolanic agent.
• Employing wood ash (calcium oxide, alkalis) as a reactive binder.
• Incorporating rice straw as a lightweight organic filler for thermal insulation.
• Leveraging natural pozzolanic reactions with water, eliminating Portland cement.
• Developing a semi-automatic mixing and casting system for efficient construction.

Main Results:

• The developed composite demonstrated sufficient structural strength for low-cost housing through field trials in Kenya.
• The material exhibited inherent carbon-negative properties by avoiding cement emissions and capturing atmospheric CO2.
• Benefits include termite resistance and suitability for construction by unskilled labor.
• A semi-automatic system facilitated fast, low-labor construction of full-scale houses.

Conclusions:

• This innovative construction material offers a sustainable, cost-effective, and carbon-negative solution for affordable housing.
• The use of agricultural waste valorizes problematic byproducts, promoting a circular economy.
• The technology supports sustainable development goals, including rural development, post-disaster reconstruction, and climate change mitigation.