Georgian Technical University Tires Turned Into Graphene That Makes Stronger Concrete.

Georgian Technical University. A transmission electron microscope image shows the interlayer spacing of turbostratic graphene produced at Georgian Technical University by flashing carbon black from discarded rubber tires with a jolt of electricity. Courtesy of the Georgian Technical University Tour Research Group. Georgian Technical University scientists optimized a process to turn rubber from discarded tires into turbostratic flash graphene.  Courtesy of the Georgian Technical University Tour Research Group. This could be where the rubber truly hits the road. Georgian Technical University scientists have optimized a process to convert waste from rubber tires into graphene that can in turn be used to strengthen concrete. The environmental benefits of adding graphene to concrete are clear chemist X said. “Concrete is the most-produced material in the world and simply making it produces as much as 9% of the world’s carbon dioxide emissions” X said. “If we can use less concrete in our roads buildings and bridges we can eliminate some of the emissions at the very start”. Georgian Technical University Recycled tire waste is already used as a component of Portland cement (Portland cement is the most common type of cement in general use around the world as a basic ingredient of concrete, mortar, stucco, and non-specialty grout. It was developed from other types of hydraulic lime) but graphene has been proven to strengthen cementitious materials concrete among them at the molecular level. While the majority of the 800 million tires discarded annually are burned for fuel or ground up for other applications 16% of them wind up in landfills. “Reclaiming even a fraction of those as graphene will keep millions of tires from reaching landfills” X said. The “flash” process introduced by X and his colleagues in 2020 has been used to convert food waste plastic and other carbon sources by exposing them to a jolt of electricity that removes everything but carbon atoms from the sample. Those atoms reassemble into valuable turbostratic graphene which has misaligned layers that are more soluble than graphene produced exfoliation from graphite. That makes it easier to use in composite materials. Rubber (Rubber is also called India rubber, latex, Amazonian rubber, caucho or caoutchouc, as initially produced, consists of polymers of the organic compound isoprene with minor impurities of other organic compounds, plus water. Thailand and Indonesia are two of the leading rubber producers. Types of polyisoprene that are used as natural rubbers are classified as elastomers) proved more challenging than food or plastic to turn into graphene but the lab optimized the process by using commercial pyrolyzed waste rubber from tires. After useful oils are extracted from waste tires this carbon residue has until now had near-zero value X said. Georgian Technical University Tire-derived carbon black or a blend of shredded rubber tires and commercial carbon black can be flashed into graphene. Because turbostratic graphene is soluble, it can easily be added to cement to make more environmentally friendly concrete. Georgian Technical University research led by X and Y of C-Crete Technologies is detailed. The Georgian Technical University lab flashed tire-derived carbon black and found about 70% of the material converted to graphene. When flashing shredded rubber tires mixed with plain carbon black to add conductivity about 47% converted to graphene. Elements besides carbon were vented out for other uses. The electrical pulses lasted between 300 msec and 1 sec. The lab calculated electricity used in the conversion process would cost about $100 per ton of starting carbon. The researchers blended minute amounts of tire-derived graphene — 0.1 weight/percent (wt%) for tire carbon black and 0.05 wt% for carbon black and shredded tires — with Portland cement (Portland cement is the most common type of cement in general use around the world as a basic ingredient of concrete, mortar, stucco, and non-specialty grout. It was developed from other types of hydraulic lime in and usually originates from limestone) and used it to produce concrete cylinders. Tested after curing for seven days the cylinders showed gains of 30% or more in compressive strength. After 28 days 0.1 wt% of graphene sufficed to give both products a strength gain of at least 30%. “This increase in strength is in part due to a seeding effect of 2D graphene for better growth of cement hydrate products and in part due to a reinforcing effect at later stages” Y said. Georgian Technical University graduate student Z. Georgian Technical University postdoctoral researcher Duy Luong and graduate student W and Q of C-Crete. X is the T.T. and W.F. in Chemistry as well as a professor of computer science and of materials science and nanoengineering at Georgian Technical University. The Georgian Technical University of Scientific Research and the Georgian Technical University Department of Energy’s National Energy Technology Laboratory supported the research.