Study On Dry-mixed Mortar

The traditional mortar with single variety and inferior performance has not accommodated to demands of actual building project, therefore, building mortar should be specialized and Dry-mixed mortar should be developed.Influences of basic component (fiber, redispersable emulsoid powder, water-retentive admixture, expansive admixture, mixture and cement-to-sand ratio )of Dry-mixed Mortar on essential performance of mortar have firstly been summarized. The results show that : (1) After fiber is mixed into Dry-mixed Mortar , toughness ,crack resistance and unpermeability of mortar will be improved; Influence of different length mixed fiber on toughness of mortar precedes single-length fiber, but influence on crack resistance of mortar is the same. (2) In the redispersable powders, WACER powder is excellent. When fine percentage of redispersable emulsoid powder is 1, toughness, adhesive performance of mortar have improved. (3) When MC was mixed into mortar, water-retentive performance, toughness, adhesive performance of mortar have improved and 28d dry shrinkage of mortar has reduced. (4) When AEA was mixed into mortar, dry shrinkage of mortar reduced and infiltration resistance has improved. (5) When cement-to-sand ratio is 1:2.5 , toughness of mortar is perfect. (6) mixture is mixed into mortar , toughness of mortar has improved ,but adhesive performance is inferior. Based on the study result , in order to overcome desquamation of ceramic tile and crack and cavitations of masonry metope , the two special dry-mixed mortar have been compounded: (1)Basic component of ceramic tile banding mortar is : cement: sand: redispersion emulsoid powder: MC= 1:2.5:0.007:0.002. (2) Basic component of masonry mortar is : cement : sand : redispersion emulsoid powder: MC: AEA=1:2.5:0.015:0.002:0.08. Because the two special mortar is a single system, they are mixed with water to be used.Finally the modified mechanism of fiber, redispersion emulsoid powder, water-retentive admixture and expansive admixture have been analyzed.