Abstract

Proper bonding of coatings and linings to concrete surfaces requires proper cleaning and frequently requires the concrete to be roughened to increase the surface area. The roughness, also known as surface profile, can be imparted into concrete by abrasive blast cleaning, acid etching, or various impact/scarifying power tools. The resulting surface profile depth can influence coating/lining adhesion and performance. Coating/lining manufacturers and/or facility owners frequently specify cleaning and roughening of the concrete surface prior to product installation.

The surface profile (roughness) of prepared concrete can be assessed visually using Concrete Surface Profile (CSP) Chips such as those described in Guideline No. 310.2R, Selecting and Specifying Concrete Surface Preparation for Sealers, Coatings, Polymer Overlays, and Concrete Repair produced by the International Concrete Repair Institute (ICRI), or by creating a replica of the prepared surface using an epoxy putty as described in ASTM D7682, Standard Test Method for Replication and Measurement of Concrete Surface Profiles Using Replica Putty and comparing it to the specified ICRI chip (Method A) or taking depth micrometer measurements from the replica (Method B). ASTM D8271, Standard Test Method for the Direct Measurement of Surface Profile of Prepared Concrete describes a procedure for acquiring measurements directly from the prepared concrete using an electronic depth micrometer. Most recently, Technical Applications for Concrete Materials (TACM) has made available concrete samples that are mechanically (or chemically) processed by the actual methods used to obtain the ICRI CSP® profiles on a construction jobsite. AMPP Standard Committee 12 (SC 12) on Concrete Infrastructure is developing a new standard titled Procedure for Determining Conformance to Concrete Surface Profile Requirements to address the frequency and acceptability of concrete surface profile measurements using any of these methods (Note: AMPP SP21513-2021 was approved October 6, 2021).

The CSP Chips produced by ICRI are arguably the most widely recognized and most frequently specified method to assess concrete roughness; however, this method (as well as the newer TACM concrete samples) is qualitative and requires some judgement. The procedures described in ASTM D7682 (Method B) and ASTM D8271 are quantitative but are not widely specified. There was perceived value in correlating the qualitative and quantitative methods of assessing the surface profile of prepared concrete so that specifiers can specify either, without inadvertently invoking contradictory requirements.

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