Effects of Laser Cleaning on Chemical Composition of Mortar Surfaces

Abstract

The paper presents a part of the larger study on microstructural features of mortars and their effects on laser cleaning process. It focuses on presenting the results of investigation on the influence of laser cleaning on chemical composition of mortar surfaces. The experimental results prove that the laser cleaning process leads to an increase of Si element concentration and/or decrease in Ca concentration. The observed alterations should be associated with changes in the relative distribution of melted cement paste and aggregate and therefore relative elemental abundance in the near-surface layer. Furthermore, curing and service conditions of mortars seem to have strong influence on laser cleaning process and therefore on surface quality. Exposure to freezing/thawing cycles and subsequent surface damage facilitates deeper penetration of paint and consequently affects the efficiency of cleaning. The amount of residual carbon on F/T samples tested in the course of this study was around 42% higher than on the surfaces of laboratory-cured samples.