Effect of temperature and additives on recycled waterborne coating preparation and performance for construction and demolition waste reutilization

Construction and demolition waste (C&D waste) recycled and reused as the substitution of construction material is a promising method for C&D waste treatment and management. To broaden the application possibility under different temperature conditions and improve waste consumption, the effects of temperature and additives on the recycled coating performance were investigated in this study. Choosing scrubbing resistance as the performance evaluation index, the recycled waterborne coating exhibited relatively outstanding scrubbing resistance when emulsion Tg was between 22.3 and 30.5 °C around the ambient temperature. This further implied that the application of an appropriate Tg according to the painting temperature could result in achieving the desired coating. The film-forming additives tests for the recycled brick powder waterborne coating system were found to be effective in improving the coating’s performance, with ranking: alcohol ester dodecyl > propylene glycol > glycol, due to the MFFT reduction. For the adding mode perspective, the mixed-additives treatment (over 7% addition) displayed more effective than single-additive treatment, achieving a twofold increase in coating performance at 35 °C and a fourfold to sixfold increase at 40 °C. The film-forming additives, particularly the mixed-additives treatment, not only broaden the application temperature range at low temperatures, but also strengthen the coating’s performance at high temperatures.