Mechanical properties and anti-efflorescence of cement-based coating containing silicon-aluminum based powder and modified-polyacrylate emulsion

The objective of this paper was to prepare a novel type of anti-efflorescence cement-based coating with excellent mechanical properties using the modified polyacrylate emulsion (MP) and silicon-aluminum based powder (SA), and provided an optimum proportion. Silica sol (SS) and polydimethylsiloxane (PDMS) were selected as modified components to incorporate into polyacrylate emulsion (PA). The synergistic effect of MP and SA on the tensile strength, water absorption, hydration process, microstructure and anti-efflorescence property of cement-based coatings were investigated. The research results demonstrated that the tensile strength and waterproof in coating containing MP and 0.3 wt% SA were increased by about 73.4% and 52.1%, respectively, compared with the reference sample. The reason could be attributed to the densification of the internal structure due to the formation of “Si-O-Si” structure and pozzolanic effect of SA. In addition, the hydrophobic PDMS can hinder the migration of water and salt, thereby limiting the diffusion of alkali ions outward. Hence, the efflorescence area of the modified-coating was decreased to 1.58%.