Mortar Block Surface Preparation and ASTM C 794

Historically, the results of ASTM C 794 Adhesion-In-Pee1 tests have been subject to high variation, especially in tests on mortar where results from different laboratories were compared. This experiment focuses on one potential source of error, the method used to prepare the surface of the mortar block. Five different techniques were evaluated with three generically distinct sealant types all intended for use on concrete and mortar. The procedures described in ASTM C 794 were followed as closely as possible. The results are evaluated for differences in precision which can be attributed to the substrate.