Kenaf-based building material shows promise
[OUAGADOUGOU, BURKINA FASO] Researchers from Burkina Faso and France have developed a low-cost construction material made of clay and sand mixed with fibres from the kenaf plant.
Kenaf is member of the cotton family, and its fibres are already widely used in Burkina Faso to make bags and ropes, as well as other products typically made from wood, like paper.
Jacob Sanou, of the Farako-Ba research station of Bobo-Dioulasso, in Burkina Faso, says he was inspired to try using kenaf to make building materials by the flax plant, which Europeans have used in a wide range of products including clothing, paper and industrial products.
Sanou joined forces with two specialists in composite materials based in France — Philippe Blanchart, from the National School of Industrial Ceramics at the University of Limoges, and Moussa Gomina, a Burkinabé researcher at the University of Caen.
They developed a kenaf composite material that is cheaper and stronger than ordinary building materials, and provides excellent insulation in the hot climate, as well as blocking out sound.
The team studied kenaf farming practices and found that the plant has no detrimental effect on soil quality, and even without fertiliser, average yields are around four tonnes per hectare, making it a potentially valuable and environmentally sustainable crop.
The work paves the way for rural farming communities to build comfortable, affordable homes for themselves and their families without damaging the environment, Sanou told SciDev.Net.
"Our study suggests that kenaf has good potential as a building material," he said, adding that more research is needed to determine its commercial viability.
Burkina Faso's minister in charge of scientific research and innovation, Gnissa Konaté, said the work is of considerable interest to the government, which has recently prioritised the building sector and eco-materials under its latest research policy.
Konaté added that the country's climate poses challenges for conventional building materials.
"Construction with cement is not adapted to the warm climatic conditions of Burkina Faso," he said.
"Cement stores heat, so buildings which are made from this material consume more energy due to their reliance on air conditioners. Combining kenaf with local clay was an unexpected success, which the authorities are willing to seize in order to stir up the building sector in Burkina Faso."
Further laboratory studies will be carried out at the University of Ougadougou and civil engineering colleges, says Sadou.