Parametric study on polymer-modified pigmented cementitious overlays for colored applications

Limited studies addressed the concurrent effects of iron oxide pigments (IOPs) and styrene-butadiene rubber (SBR) latexes on properties of self-leveling mortars (SLMs) intended for decorative and aesthetic overlays. Different mortar series prepared with 0.45-0.6 water-to-cement ratio (w/c), 2%-8% yellow or red colored IOP, and 5%-15% SBR are investigated. Test results showed that fresh SLM rheological properties including yield stress and plastic viscosity are highly affected by the IOP fineness, morphology (spherical vs. elongated), and concentration. Mixtures incorporating low IOP rates (i.e., less than 4%) exhibited relatively higher strengths and bond to existing substrates. The flexural and bonding strengths remarkably improved with SBR additions, given the stronger interfacial bonds created between such polymers and the cementitious matrix. Particular emphasis was placed to develop regression models and charts that enable predicting key SLM properties including color coordinates, rheological properties, flexural/compressive strength, and bond to existing substrates.