bond plaster, concrete bond plaster
A mill-mixed gypsum plaster containing a small percentage of lime; just before application it is mixed with water only and then applied to a maximum thickness of 1/4 in. (0.6 cm) over prepared concrete surfaces. It serves as the bond between the concrete and succeeding coats of gypsum plaster.
McGraw-Hill Dictionary of Architecture and Construction. Copyright © 2003 by McGraw-Hill Companies, Inc.