Impact of Concrete Mix Ingredients and Surface Treatments on Epoxy Overlay Performance

Epoxy overlays are applied on bridge decks with new concrete in patches and repairs after 28 days of curing. Tensile bond pull-off strength of at least 250 psi is expected from a properly applied overlay. Even though the overlay performance under room temperature is mostly satisfactory, the performance under elevated temperature is not convincing. The degradation of mechanical and adhesion properties of epoxy, shear stress development at concrete/overlay interface due to thermal incompatibility, and moisture vapor pressure at the interface are commonly cited among many parameters that could contribute to the poor performance of an epoxy overlay. A combined effect of these factors results in the most unfavorable failure mode, bond failure at the concrete/overlay interface, at a strength lower than the specified limit of 250 psi. The moisture migration through concrete depends on many factors including moisture content along the depth of concrete, pore microstructure, exposure condition, and drying period. This study investigated the impact of concrete mix ingredients and surface treatments on the thin epoxy overlay bond strength. The results show that the use of slag in mixes and penetrating sealant pretreatment improves the bond strength.

Language

  • English

Media Info

  • Media Type: Digital/other
  • Features: Figures; References; Tables;
  • Pagination: 16p

Subject/Index Terms

Filing Info

  • Accession Number: 01763436
  • Record Type: Publication
  • Report/Paper Numbers: TRBAM-21-04021
  • Files: TRIS, TRB, ATRI
  • Created Date: Dec 23 2020 10:59AM