The influence of a high power diode laser (HPDL) generated glaze on the wetting characteristics and the subsequent HPDL enamelling of ordinary Portland cement

High power diode laser (HPDL) surface glazing of the ordinary Portland ceme nt (OPC) surface of concrete was found to effect significant changes in the wettability characteristics of the OPC. This behaviour was identified as b eing primarily due to: (i) the polar component of the OPC surface energy in creasing after HPDL glazing from 3.46 to 15.56 mJ m(-2); (ii) the surface r oughness of the OPC decreasing from an Rn value of 21.91 to 2.88 mum after HPDL glazing; and (iii) the relative surface O-2 content of the OPC increas ing by 4.5 at.% after HPDL glazing. HPDL glazing was consequently identifie d as occasioning: a decrease in the enamel contact angle from an initial va lue of 109-31 degrees, thus allowing the vitreous enamel to wet the OPC sur face. (C) 2001 Elsevier Science B.V. All rights reserved.