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Peeling test

 

DOWNLOAD: click here to download (90Mb)

 

Introduction

The main aim of the test is to reveal strength/cohesion of studied surface. A sequence of adhesive tape strips is one by one applied to the surface and then removed = peeled off while the weight of the removed material is measured on a laboratory scales. The freely provided software allows user to evaluate the measurement sequence and separate deterioration of the surface from its bulk strength. The application consists of the executable program and auxiliary libraries.

 

Surface degradation model

Analyzing the sequence of removed material’s weights m(n), one can, essentially, find two components: the transitional one related to the surface deterioration and the constant one, reflecting intact bulk cohesion of the intact material.

 image001.png

According to the peeling-test model, unperturbed material’s cohesion manifests itself as constant amount of removed material in peeling sequence, in the formula denoted as A. This weight corresponds to the fragments broken apart from the surface in the process of affixing the strip on the surface. It assumes that this component would remain constant if the peeling is repeated again and again. The second component of the weight in the sequence is a measure of deterioration of the studied surface and its depth profile – the higher the ratio B to A, the more significant the degradation is. The exponent C reveals depth into which the degraded layer propagates – the bigger the C value is the steeper is decrease of removed weight, the thinner degraded layer is. The following figure explains meaning of the parameters A, B and C.

 

The number of ten strips per one kit is suitable for determination of the formula parameters A, B and C, therefore is used the most.

image004.jpg

 

Comparative tests

Putting statistics aside, two, resp. three tests are necessary in order to compare effectivity of the surface treatment to doing nothing, resp. to compare the effectivity of treating the surface with another agent, or e.g. with a distilled water applied the same way as consolidant. The last mentioned case refers to the fact, that some part of weathered/deteriorated surface can be „brushed off“ merely by the application technique resulting in seemingly improved surface. The subplots d and f in the following figure depicts peeling behaviour of untreated deteriorated mortar surface. Subplots e and g show changed peeling properties of surface after treatment by CaLoSil: the surface was signifiantly improved by the treatment.

image010.jpg

 

Experimental procedure

In a sequence of pockets from #1 to #10, the proper peeling-test procedure is as follows: 

  1. Pick the pocket of the proper number
  2. remove self-adhesive strip from zip-lock pocket
  3. remove film covering the adhesive part of the strip
  4. apply  the strip on the studied surface, applying moderate pressure evenly
  5. remove the strip from the surface and cover it by the film previously removed
  6. put it into the zip-lock pocket again

Weight it on laboratory scales, the measured weights are supposed to be determined to four valid digits.

image010.jpg

Data processing

The measured values have to be processed in the following way:

  1. Weight of the given pocket number can be found printed on the kit envelope
  2. The net weight of the removed material is a difference between pocket weight after application and before application. The second value can be found printed on the kit envelope. The weight of material removed from the tested surface is determined as a difference between weight of the „pocket“ after and before its application on the surface.
  3. The weight sequence should be stored in one column of numbers in a text (.txt or .dat extension) file, one value per one line.
  4. Data file is then processed by the freely provided application.
  5.  

Using a free application for peeling evaluation

  1. Installation
    • a. The zipped directory containing the program and libraries can be downloaded (click here to download, 90Mb) from the webpage:  http://www.itam.cas.cz/Software/peeling-test .
    • b. After download, folder „peeling-test“ should be created by unzipping.
    • c. As the application is based on Matlab libraries, those have to be installed first. In subfolder „win32“ of the uzipped „peeling-test“ folder, file „MCRInstaller.msi“ can be found. Double-click would install these libraries in system suggested location and in a manner usual for Windows application.
  2. Running the application
    • a. The application for evaluation called „peeldatf.exe“  then can be started double-clicking its icon in the „peeling-test“ directory.
    • b. In the next step a file containing the weight data has to be determined in the standard window for file selection.
  3. Results

Finally, application displays a plot of measured weights and also best fit curve for data model to this formula. Formula parameters are displayed in the title of the plot. The plot can be saved in various formats.

 

Warning:

The adhesive tape strips can attach to the surface with a remarkable adhesive force and therefore during removal a substantial amount of material can be removed from the surface. As a result it is advisable to evaluate the peeling test on the areas less visually exposed first. The warning is especially valid for very fragile and loose surfaces.

 

Contact

Questions and requirements should be addressed to itam.

 

Disclaimer:

The author, of this software accepts no responsibility for damages resulting from the use of this product and makes no warranty or representation, either express or implied, including but not limited to, any implied warranty of merchantability or fitness for a particular purpose. This software is provided "AS IS", and you, its user, assume all risks when using it.