Assessment of the constancy of performance of cementitious adhesives for ceramic tiles: Analysis of the test results commissioned by polish market surveillance authorities

Abstract

Assessment and verification of constancy of performance (AVCP) is a complex process. Without it, the manufacturer cannot mark the product with the Conformite Europeenne (CE) marking and place it on the EU market. The verification of the correctness of the AVCP is carried out by market surveillance. In Poland, supervision authorities regularly check manufacturers by collecting construction products that exist on the market for inspection. Among the dry-mix mortars, adhesives for ceramic tiles (CTA) constitute an essential group. The requirements for CTAs are specified in EN 12004. According to the standard, the basic characteristics of cementitious CTAs are tensile adhesion strength and open time. The adhesion measurements are performed after various laboratory conditions tests. The study analyzes the results obtained for 129 samples of cementitious CTAs, collected between the years 2016 and 2019 from the market, and tested in notified laboratories at the request of Polish construction supervision authorities. Many tested products did not meet the threshold values, which resulted in removing them from the market. The paper discusses the complexity of the tensile adhesion strength measurement. The obtained test results are considered in various dimensions, including using the simple acceptance rule method when evaluating the results, which does not consider the measurement uncertainty.