The Effect of Adding Steel Fibers and Graphite on Mechanical and Electrical Behaviors of Asphalt Concrete

Abstract

Conductive asphalt concrete can satisfy different and multifunctional applications such as heating roads to get rid of snow and ice and assure auto-detection, auto-cure, and energy recovery. This research aims to evaluate the performance of asphalt concrete with additives like steel fibers and graphite powder. This work is based on destructive tests (direct tensile test FENIX) and non-destructive tests (electrical resistivity measures). The obtained results indicate that the tensile resistance, dissipated energy, and ductility module of asphalt concrete increased with the increasing steel fiber percentage. Direct tensile strength, cracking resistance, and dissipated energy increased as graphite percentage increased, while the ductility module decreased. Electrical resistivity decreased when it added steel fibers and graphite. Therefore, it found that tensile strength increased reversibly with electrical resistance. When adding steel fibers or graphite powder, the dissipated energy of asphalt concrete is increased while electrical resistivity is decreased. The dissipated energy of conductive asphalt concrete with steel fibers is higher than that with graphite powder. Electrical resistivity decreased significantly with increasing steel fibers, compared to electrical resistivity with graphite. The obtained results indicate that asphalt concrete cracking resistance is higher with the optimal percentage of steel fibers added at 1% and better mechanical performance. Doi: 10.28991/CEJ-2022-08-02-012 Full Text: PDF

A review of conductive additives for enhancing the electrical properties of self-sensing asphalt

“…To make asphalt self-sensing, either the asphalt mastic shall contain conductive additives, or the aggregates in itself shall be conductive [25]. Electrically Conductive Materials (ECM), or Conductive Phase Materials (CPM), or simply conductive additives, are self-sensing, self-monitoring, multifunctional or smart materials usually introduced in asphalt mastic for ideally enhancing its electrical conductivity without compromising its fundamental performance parameters [7,9,[16][17][18][26][27][28]. The first attempt of such development dates back to 1950s [16,28] and the 1960 [9], whereas the first patent related to conductive asphalt was issued in 1965 [22].…”

“…Graphite a common carbon allotrope and exhibit advantages such as a stable crystal structure, excellent electrical conduction, low cost, chemical compatibility with asphalt binder, inert, non-toxic, and exists in many types depending on shape, size, origin and manufacturingall these features may vary asphalt's electrical conductivity phenomenon [8,13,16,21,27]. It is a commonly used binderbased additive which improves conductivity and enhances indirect tensile/mechanical strength due to its hydrophobic nature, same as asphalt binder, and offers strong adhesion with it [8,29].…”

“…Independent of the above classifications, previous research studies have used several types of additives for imparting electrical conductivity into asphalt, the most commonly used ones are carbon fiber, steel fiber, aluminum fiber, steel wool [6,33,38], carbon nanotube [26,39], graphene (nanometer-level) [6], graphite powder (micrometer-level), carbon black, nickel powder, TA [18], copper slag [40], coke [19], metal and steel shaving etc. [18,26,27,29,35,37,40].…”