Removal of graffiti from the mortar using Q-switched Nd:YAG laser

Poologanathan Sanjeevan, Agnieszka J. Klemm, Piotr Klemm

Research output: Contribution to journalArticle

Abstract

This paper presents part of the larger study on microstructural features of mortars and the effects on laser cleaning process. It focuses on the influence of surface roughness, porosity and moisture content of mortars on the removal of graffiti by Nd: YAG laser. The properties of this laser are as follows: wavelength (¿) 1.06µm, energy: 500 mJ per pulse, pulse duration: 10 ns. The investigation shows that the variation of laser fluence with the number of pulses required for the laser cleaning can be divided into two zones namely effective zone and ineffective zone. There is a linear relationship observed between number of pulses required for laser cleaning and the laser fluence in the effective zone, while the number of pulses required for the laser cleaning is almost constant even though the laser fluence increases in the ineffective zone. Moreover, surface roughness, porosity and moisture content of mortar samples have influence on the laser cleaning process. The effect of these parameters become however negligible at the high level of laser fluence. The number of pulses required for the laser cleaning is low for smooth surface or less porous mortar. Furthermore, the wetness of the samples facilitates the cleaning process.
Original languageEnglish
Pages (from-to)8543-8553
Number of pages11
JournalApplied Surface Science
Volume254
Issue number20
Early online date22 Apr 2007
DOIs
Publication statusPublished - Aug 2007

Keywords

  • graffiti
  • laser cleaning
  • moisture content
  • porosity
  • surface roughness

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