Mechanical and electrical properties of concrete incorporating an iron-particle contained nano-graphite by-product

Abstract

Electrically conductive cementitious composites (ECCC) have a wide range of potential applications in advanced structural technologies such as structural health monitoring and pavement deicing. General conductive fillers, such as steel fiber, carbon nanofiber and carbon nanotube, have been investigated to enhance the ECCC conductivity. However, cheaper and more efficient conductive fillers are required to promote the wider application of ECCC. The present study applies an iron-particle contained composite nano-graphite by-product (ING) to investigate a new type of conductive concrete. Both mechanical and electrical properties of this conductive concrete are examined and compared with corresponding measured properties of plain concrete and composites incorporating pure nano-graphite (NG). Results show a loss in compressive strength and increase in conductivity of concrete due to the addition of nano-graphite materials. A 1 wt% content of ING leads to almost 20% reduction in concrete’s compressive strength compared with the plain concrete, which is larger than NG (only 6.3%). However, the mechanical behavior of concrete with ING is little better than that of concrete with NG at 3 wt% and 5 wt%. ING is more significant in enhancing concrete conductivity than NG, especially at 1 wt% by resulting in a 70.3% decrease in electrical resistivity while only 11.3% resistivity reduction is observed for NG at the same concentration. Microstructural images show that composites incorporating ING material reach the percolation threshold of resistivity sooner. Meanwhile, ING particles show agglomerated state within the concrete matrix while NG tends to spread among it in the form of platelets.