Influence of vinyl acetate/ethylene copolymer powder on secondary efflorescence in Portland cement-based decorative mortar *

In this paper, the effect of redispersible vinyl acetate/ethylene copolymer powder (VAE) on the secondary efflorescence of Portland cement-based decorative mortar (PCDM) was evaluated by alkalis leachability. The secondary efflorescence substances were investigated using X-ray diffraction (XRD), X-ray fluorescence (XRF), and scanning electron microscope (SEM). The mechanism was also analyzed from the aspect of soluble components in PCDM. The results show that the secondary efflorescence level of PCDM can be quantitatively evaluated by alkalis leachability, with a higher alkali leachability indicating more obvious secondary efflorescence. VAE increases the concentrations of free alkalis ions including Ca2+, K+, Na+ of PCDM, improves the capacity of pore water transmitting ions, increases the alkalis leachability of PCDM, and accordingly promotes the secondary efflorescence of PCDM.