A team of researchers from the Rensselaer Polytechnic Institute (RPI), USA, has invented hemp-based rebar as an alternative to traditional steel reinforcement for concrete structures. The study claims that hemp rebars for concrete reinforcement mitigate the problem of corrosion and reduce carbon emissions.
Image Credits: Alex Tsamis/courtesy Rensselaer Polytechnic Institute (RTI), USA
There are many natural fibers like bamboo, sisal, etc., with a strength similar to steel. When combined with a plant-based bioplastic, hemp fibers could be an alternative to steel rebars.
Industrial hemp is a class of cannabis sativa plant whose fiber is the strongest in the plant kingdom. It is as strong as glass fiber on a per weight basis. Hemp plants have the ability to capture atmospheric carbon twice more effectively than trees. Hence, it is a carbon-negative biomaterial for architects and designers.
Hemp-based rebars are made using the hearty fibers of the hemp stalk. These fibers are combined with a resin or bioplastic to form bars similar to steel reinforcement.
Image Credits: Dezeen
The production process involves the pultrusion process, where the fibers are pulled together with thermoplastic into a heated dye, which is melted to form a solid bar. The machinery used to make hemp rebars was developed by Tsamis and Walczyk and their team.Â
Preliminary results obtained by the research team showed that hemp rebar possesses a significantly lower amount of embodied energy than glass fiber reinforced polymer (GFRB) rebars. Unlike other non-corrodible reinforcement alternatives for steel, hemp rebars are cheaper than standard steel rebars.Â
Eliminating steel reinforcement bars and replacing them with a non-corrosive alternative can eliminate the corrosion risk faced by most R.C.C structures, which could last decades longer.
After undergoing a few reviews and tests, the team expects hemp rebars to be open and recommended for buildings within a few years.
Hemp plantation is legalized in the US. Even though the crop is highly climate-resilient, its cultivation is not rapid and is not found attractive to farmers because of the lack of high-value products it offers. This can be changed by the innovation of low-cost non-corroding rebars from hemp that could be an alternative for steel rebars.
FAQs
Hemp-based rebars are made using the hearty fibers of the hemp stalk. These fibers are combined with a resin or bioplastic to form bars similar to steel reinforcement.
The hemp rebars production process involves the pultrusion process, where the hemp fibers are pulled together with thermoplastic into a heated die, which is melted to form a solid bar. The machinery used to make hemp rebars was developed by Tsamis and Walczyk and their team at the Rensselaer Polytechnic Institute (RPI), USA.
The studies show that hemp rebar possesses a significantly lower amount of embodied energy than glass fiber reinforced polymer (GFRB) rebars. They are also low-cost non-corroding rebars.
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