Fabrication of negative carbon superhydrophobic self-cleaning concrete coating: High added-value utilization of recycled powders

In this work, two cost-effective methods for preparing negative carbon superhydrophobic self-cleaning concrete coatings were developed by using silane-modified recycled powders (RP) from concrete and carbonated & silane-modified RP. The effects of silane-modification and carbonation on RP, the surface roughness and performances of RP coatings were investigated. The results showed that both methods achieved negative carbon emission. RP and carbonated RP were successfully modified by silane, and two possible silane modification mechanisms corresponding to the two methods were proposed. Surface rough structures of the two coatings were formed by the stacking of powders on the surface of cement paste, which both exhibited excellent superhydrophobicity. In addition, both coatings presented desirable mechanical properties, weathering resistance and chemical stabilities in performances tests. These two high added-value utilization methods of RP are considered to be of great significance to low-carbon city construction and green economic development.