A New Building Material: Wood Fiber Concrete
“Scientists have worked on a method for recycling unused concrete with wood fibers. They produced wood fiber concrete, a new building material with greater flexural strength than the original concrete. This work can help reduce CO2 emissions associated with new concrete production.”
Concrete has long been a favorite building material used in many structures such as skyscrapers, bridges and houses, and preferred in the construction of our modern world.
However, concrete production has come under intense scrutiny as countries try to limit greenhouse emissions. Concrete consists of aggregate – usually made of gravel and crushed stone – and cement.
Cement production is responsible for the large amount of carbon dioxide that humans emit into the atmosphere.
Researchers at the Institute of Industrial Sciences, part of the University of Tokyo, have developed a new procedure for recycling concrete with the admixture of waste wood.
Wood gets its hardness from lignin, a highly cross-linked organic polymer. In the combination of wood and concrete, lignin fills the voids in the concrete and acts as an adhesive when mixed with waste concrete powder and heated.
The researchers optimized their method by adjusting the mixing ratio, pressure, temperature, pressing time, and water content.
Finding the right ratio of concrete and wood was critical to obtaining the strongest concrete.
They found that the correct ratio of inputs can provide a new building material with greater flexural strength than the original concrete.
This research can help reduce carbon emissions as well as significantly reduce construction costs.
“Many of the recycled products we make exhibited better flexural strength than regular concrete,” says senior researcher Yuya Sakai. “These findings may spur a movement towards a greener, more affordable construction industry that not only reduces waste concrete and wood warehouses but also helps address the issue of climate change.”
Recycled concrete is likely to be biodegradable because concrete waste depends on the wood component. The method could also be extended to recycle other plant wastes instead of wood.