Standardization of peeling tests for assessing the cohesion and consolidation characteristics of historic stone surfaces

Abstract

A peeling test known as the “Scotch Tape test” has been used for more than 40 years in conservation practice for assessing the consolidation efficiency of degraded stone. However, the method has not been supported by any standard or reliably verified recommendations for its application. Its applicability is overestimated, and its unrestricted use without adequate knowledge and sufficient understanding can lead to non-comparable, non-reproducible and, in many cases, incorrect and severely biased results and assessments. This paper presents the results of a recent study focused on establishing limits for application, reliable procedures and a “standard” protocol for testing the cohesion characteristics of brittle and quasi-brittle materials, mainly mortars and stones. The main application strategy exploits repeated peeling in the same place on a surface in order to eliminate the effect of the natural decrease in the detached material from the subsurface layers, which might be incorrectly interpreted as a consolidation effect. There is a discussion of factors influencing the performance of the peeling test method, and examples of peeling measurements on various natural and artificial stones are presented.

Innovative consolidating products for stone materials: field exposure tests as a valid approach for assessing durability

“…Surface cohesion characteristics of the stones before and after the consolidating treatment have been assessed by carrying out the peeling test recommended by many authors and standardized by Drdácký et al [32]. It consists in applying and removing pressure sensitive tape over the surface of interest to evaluate the amount of incoherent material peeled from the surface by gravimetrical analysis (Figure 11).…”

Photocatalytic Activity of TiO2/AuNRs–SiO2 Nanocomposites Applied to Building Materials

“…Successively, we calculated the corresponding dry matter of products and characterized the samples by the procedures described below. In order to evaluate the adherence of the coating to the stone surface, the weight loss of stone was determined by performing a peeling test using Scotch Magic tape (3 M) [36]. The mechanical properties of treated stone were evaluated by using the Vickers hardness test method, also referred to as a microhardness test method [37].…”

Complex Comparative Tests on Historic Stone

“…In relation to fracture toughness, the importance of the heterogeneity, porosity and strength of the interfaces between phases rises. The measurement procedure and a discussion of the influences on the measurement are presented in detail in (Drdáck et al 2012b). …”

“…An approximation form m(n) = A + B * e -C*n describing the sequence of weights of the removed material m(n) is also suggested in (Drdáck et al 2012b). …”