Title:
Surface Preparation for Overlays
Author(s):
James Warner, Sam Bhuyan, W. Glenn Smoak, Kal R. Hindo, and Michael M. Sprinkel
Publication:
Concrete International
Volume:
20
Issue:
5
Appears on pages(s):
43-46
Keywords:
abrasive blasting; bond; delamination; hydrodemolition; overlays; sandblasting; scabblers; scarifiers; shot blasting; surface preparation; water blasting
DOI:
Date:
5/1/1998
Abstract:
New concrete that is added to old concrete requires good bond and full transfer of shear stresses at the bond line. The need for a clean roughened surface on the parent concrete is well recognized. However, not as well understood is the reality that while some equipment can prepare surfaces for good bond, other techniques can produce inadequate surfaces, which results in poor bond or delamination. Bruising of the surface during preparation, especially with impact-type tools, can result in failure at the interface a few millimeters into the parent concrete. Acceptable preparation methods as well as those that should be avoided are discussed in this article.