Self-leveling flooring compounds:
Application, Mechanisms and Properties
A. De Gasparo , J. Kighelman , R. Zurbriggen , K. Scrivener2 & M. Herwegh1
Abstract
Self-leveling compounds (SLCs) are complex mortars modified by plasticisers, defoamers, stabilisers and redispersible powders. Usually, they are based on a mixed-binder system (CAC-OPC-C$), which is adjusted in setting by accelerators and retarders. The purpose of a SLC is to produce a leveled, smooth and hard surface on which a final cover, e.g., a carpet can be applied. The low viscosity of a freshly mixed SLC allows for segregation of mortar components, and the small application thickness of 1-10 mm causes drying to be a dominant fractionation process. As a result, the different mortar components show gradual concentrations across the mortar layer.
We used different methods for the quantitative analysis of concentration profiles. The data demonstrate that cellulose ether and quartz sand are enriched and depleted, respectively, at the mortar top. Furthermore, we show that desiccation first affects areas close to the surface, where the degree of hydration can drastically be reduced. The redispersible powder can partly compensate for that by forming strong and flexible polymer films upon drying, and good surface properties can still be achieved.
Key words: self-leveling underlayment, self-leveling compound, mixed binder, polymer modified, microstructures