THE INFLUENCE OF SURFACE ROUGHNESS ON THE OPTICAL REFLECTANCE CHARACTERISTICS OF GYPSUM-BASED COATINGS

Abstract

This study aims to systematically investigate the effect of surface roughness on the optical reflectance behavior of gypsum-based wall coatings within the framework of existing literature. Surface topography is one of the fundamental parameters determining the optical performance of materials, and the interaction of light with a surface varies depending on surface roughness and microstructural characteristics. However, it is observed that this relationship has been addressed in a limited and fragmented manner in the literature, particularly with respect to gypsum-based coatings.
Within this scope, the relationships between surface roughness (Ra), surface morphology, and optical reflectance components (diffuse and specular reflectance) were comparatively evaluated based on studies conducted on mineral-based coatings, ceramics, and other surface materials. The findings in the literature indicate that as surface roughness increases, specular reflectance decreases, while diffuse reflectance increases, resulting in a more homogeneous distribution of light on the surface. Furthermore, it is understood that not only the average roughness value but also the surface geometry and the distribution of microstructural irregularities play a decisive role in light scattering.
This study presents a holistic approach to the relationship between surface roughness and optical reflectance behavior by reinterpreting findings from different material groups within the context of gypsum-based coatings. The results indicate that the optical performance of gypsum surfaces can be directed through the control of surface microstructure and provide a conceptual framework for future experimental studies in this field.