Nanowerk April 21, 2021
Researchers at MIT performed an experimental-theoretical investigation of the electrical conductivity and resistive heating of highly heterogeneous nanocarbon–cement-based composites (pastes and mortars). Even a small voltage — as low as 5 volts — could increase the surface temperatures of their samples (approximately 5 cm3 in size) up to 41 degrees Celsius (around 100 degrees Fahrenheit). They found that electrical conductivity is determined by the electric tortuosity of a “volumetric wiring” permeating a highly heterogeneous matrix from percolation to saturation. They showed that the electric energy dissipation at the origin of the Joule heating originates from spatial electric-field fluctuations. The technology could be used for indoor floor heating, enabling radiant heating in pavements, nanocarbon cement could be used to de-ice pavements without road salt, and runways. The technology is viable for mass production at reasonable cost as it uses inexpensive carbon black. The results open venues for the sustainable development of concrete for existing and emerging green technology applications…read more. TECHNICAL ARTICLE
Experimental setup…Credit: Phys. Rev. Materials 4, 125401, 9 December 2020