Iron-fortified lumber could be a greener alternative to steel beams

Although lumber does show promise as a renewable alternative to structural materials such as steel and concrete, it still tends to be a bit weaker than those substances. Scientists have now set about addressing that shortcoming, by strengthening wood with added iron.

Led by Asst. Prof. Vivian Merk, a team of researchers at Florida Atlantic University (FAU) started out with cubes of untreated red oak hardwood. Red oak – along with hardwoods like maple, cherry and walnut – is an example of what’s known as ring-porous wood. In a nutshell, this means that it utilizes large ring-shaped internal vessels to draw water up from the tree’s roots to its leaves.

The scientists proceeded to mix ferric nitrate with potassium hydroxide, creating a hard iron oxide mineral called nanocrystalline ferrihydrite, which occurs naturally in soil and water. Utilizing a vacuum impregnation process, nanoparticles of that ferrihydrite were drawn into the wood and deposited inside of its individual cell walls.