Research On Efflorescence And Suppression Measures Of Cement Based Decorative Mortar

Efflorescence and colour difference of cement based decorative mortar，related towater migration from internal or external environment，are caused by soluble alkali orsalt in the mortar surface precipitation，that seriously affect outer wall decoration of thebuilding. Especially，the efflorescence of cement based decorative mortars is alsodifficult to cure with recurrent attacks on account of environmental conditions change.Constituent materials have a significant impact on the efflorescence of decorativemortar, thus that is very important to reveal the influence of the material composition onthe initial and secondary efflorescence. In addition, analysis and comparision of theinhibition measures of the efflorescence of decorative mortar is of great significance forthe preparation of excellent comprehensive performance of decorative mortar.This paper reports an study of the influence of constituent materials and additiveson the efflorescence of decorative mortar，and a comparision of the inhibitory effect ofseveral additives on the efflorescence of decorative mortar. We focus on the mechanismof inhibiting efflorescence of cement based decorative mortar by means of additives.The results show that:①Redispersible powder and cellulose ethers can all reduce water absorption，andimprove the waterproofness resistance, flexibility and interfacial adhesion properties ofcement decorative mortar, and effectively reduce efflorescence degree. Moreover，double mixing the two kinds of polymers can obtain better synergy. Defoamer andexpansive agent can reduce the efflorescence degree of decorative mortar, but there aresome negative effect.②The addition of limestone powder and quartz powder can both reduce waterabsorption, which improves efflorescence resistance of cement based decorative mortar.While mixing quartz powder can achieve better economic efficiency, but also canreduce water absorption，and improve the mechanical properties and efflorescenceresistance of cement based decorative mortar.③The addition of inhibit efflorescence agent and waterproofing agent can allreduce water absorptio，and improve the efflorescence resistance of cement baseddecorative mortar, in which inhibit efflorescence agent gets the best effect. In additionthe decorative mortar coated waterproofing agent obtains better inhibitory effect.④Inhibit efflorescence agents can reduce the calcium hydroxide content of cement based decorative mortar, and improve pore structure. Thus the imperfection ofthe interface area between aggregate and cement slurry can be reduced, which enhancesthe compactness of decorative mortar.