The idea is that a stalk, or culm, can be sliced into smaller pieces, which can then be bonded together to form sturdy blocks — much like conventional wood composites. A structural product of this sort could be used to construct more resilient buildings — particularly in places like China, India, and Brazil, where bamboo is abundant.
Such bamboo products are currently being developed by several companies. In a project conducted by MIT scientists, along with architects and wood processors from England and Canada, it is hoped to gain a better understanding of these materials, so that bamboo can be more effectively used structurally.
To that end, MIT researchers have now analysed the microstructure of bamboo and found that the plant is stronger and denser than North American softwoods like pine, fir, and spruce, making the grass a promising resource for composite materials.
“Bamboo grows extensively in regions where there are rapidly developing economies, so it’s an alternative building material to concrete and steel,” says MIT's Professor Lorna Gibson. “You probably wouldn’t make a skyscraper out of bamboo, but certainly smaller structures like houses and low-rise buildings.”
Gibson and her colleagues analysed sections of bamboo from the inside out, measuring the stiffness of each section at the microscale. As it turns out, bamboo is densest near its outer walls. The researchers used their data to develop a model that predicts the strength of a given section of bamboo.
The model may help wood processors determine how to assemble a particular bamboo product. As Gibson explains it, one section of bamboo may be more suitable for a given product than another: “If you wanted a bamboo beam that bends, maybe you’d want to put the denser material at the top and bottom and the less dense bits toward the middle, as the stresses in the beam are larger at the top and bottom and smaller in the middle. We’re looking at how we might optimise the selection of bamboo materials in the structure that you make.”