Disposing waste latex paints in cement-based materials – Effect on flow and rheological properties

• Effect of waste latex paint (WLP) constituents on rheology of cement pastes.
• Variations in flow of cement containing WLPs stored in different conditions.
• Optimum substitution rates of mixing water by WLP.
• Prediction of flow and rheology variations with WLP additions.

The effect of waste latex paints (WLPs) on fresh and hardened properties of cement-based materials is not well understood. In this project, WLPs were not randomly collected from waste collection sites; rather produced to ensure full traceability of composition, then stored in sealed or opened pail conditions to get expired. Test results have shown that rheological properties of cement pastes are directly affected by WLP constituents, substitution rates, and storage conditions. A series of charts were proposed to predict the variations in flow, yield stress, and plastic viscosity of pastes containing 4%, 8%, 12%, and 16% substitution rates of mixing water by WLPs. The indicative measures used for prediction included the gloss unit of paints and their pigment volume concentrations. The compressive strength slightly increased at relatively low WLP rates, but then dropped sharply at higher substitutions.