Its fibre is among the strongest in the plant kingdom, as strong as glass fibre on a per weight basis, and the crop also excels at sequestering atmospheric carbon, doing so at twice the rate of trees. Industrial hemp is a class of the cannabis sativa plant that contains only a small amount of the psychoactive compound THC. Ultra-strong hemp shows promise for multiple construction materials In the meantime they will continue to develop and test the rebar, along with a suite of other product, material and process innovations they are working on as part of a drive to develop next-generation building technology using hemp. Walczyk and Tsamis, along with their student collaborators Daniel Cohen and Sharmad Joshi, hope to publish their first paper on the technology next year. So this is on purpose a kind of John Deere-like, 'the people's machine'.' The researchers have invented a machine to forge the hemp rebar on-demand on-site 'It is a material that needs to be communicated to every contractor, every builder in every village everywhere in the world. 'Rebar is an everyday material,' said Tsamis. This has also influenced the design of the on-site pultrusion machine, which Tsamis describes as having a 'John Deere' aesthetic, in reference to the tractor and heavy equipment company. Their goal is to make the product the obvious choice even for projects without big budgets or sustainability goals. Walczyk and Tsamis also intend for it to be cost-competitive with or cheaper than standard steel rebar, unlike other non-corrodible alternatives currently available.

Hemp rebar could cut construction time while keeping cost lowĪ bonus of this process is that it should decrease construction time. This device, a CNC machine about the size of a small car, sits on-site and forges the rebar on demand, reading from digital files to bend and cut the product to the stipulated shape. The first step is to make the hemp into a rope containing a blend of natural and plastic fibres – the exact 'recipe' for which the RPI team is still finessing.Ĭoils of this rope are then fed into a machine created especially for the process. The hemp rebar is made through a pultrusion process in which the fibres are pulled together with thermoplastics into a heated die and melted to form a solid bar. The team from Rensselaer Polytechnic Institute is experimenting with different thermoplastics for the mixture, including polypropylene The team says their preliminary results show the hemp rebar has a significantly lower amount of embodied energy than GFRP rebar while likely being as long-lasting, although the work is yet to be peer-reviewed. However, structural designs in highly corrosive environments will often use alternatives to traditional steel such as glass fibre reinforced polymer (GFRP) rebar, which has a high environmental impact. Read: Ten future materials that could change the way we build

Number 15 rebar