Preparation And Study On Extra Fine Sand Dry-mixed Mortar

Building mortar is one of the most universal building-engineering materials,and the primary function of mortar in building are adhension,laying and stress transmission. But the traditional building-mortar is usually blent into in the construction local,which possesses many defects such as low accuracy of mixture ratio, fine aggregate grading is not reasonable,difficult in using addition agent,poor stability of quality,low adherence power, contractility of bigness,low cracking resistance and impermeability, thus the traditional mortar may resulting in lots of engineering quality accidents such as crack in the wall,swelling and penetration.Mortar made in the local is at the cost of wasting materials and contaminating environment.Therefore,it's important to specialize building mortar.There has been a new commercial industry that mortar is mixted at a large scale in advanced country.Commercial mortar is divided into two forms between Wet-mortar and Dry-mixed Mortar,and the latter is developing in our country.Due to many advantages such as good stability of quality,more variety,agility and adjustability, Dry-mixed Mortar in our country encounters large market and development interspace. Research on fine sand mortar is limited,and fine sand mortar is more easy to result in engineering quality accidents,thus we research fine sand Dry-mixed Mortar. Influences of redispersable emulsoid powder, water-retentive admixture, fiber,fly ash and expansive admixture on essential performance of mortar have firstly been summarized. The results show that : (1) After redispersable emulsoid powder is mixed into Dry-mixed Mortar ,the workability and adhesive performance of mortar have improved,but other mechannice index reduced. (2) When MA was mixed into Dry-mixed mortar, water-retentive performance, toughness of mortar have improved,but mechannice performance reduced. (3) After fiber is mixed into Dry-mixed Mortar , toughness ,crack resistance of mortar will be improved,and dry shrinkage of mortar has reduced. (4) When fly ash was mixed into Dry-mixed mortar,the workability of mortar improved but mechannice performance reduced. (5) When GNA was mixed into mortar, dry shrinkage of mortar reduced and crack resistance has improved. Based on the study result , several special dry-mixed mortar have been compounded: (1)Basic component of ceramic tile banding mortar is : cement: sand: VAE: MA= 1:2:0.007:0.0015. (2) Basic component of masonry mortar is : cement : sand : VAE: MA: GNA=1:2.5:0.01:0.0015:0.08, and the fiber contents is1 Kg/m~3 . (3) Basic component of normal crack resistance mortar is: cement : sand : VAE: MA: GNA=1:2:0.007:0.001:0.10, and the fiber contents is 1.3 Kg/m3 . Finally the modified mechanism of redispersable emulsoid powder, water-retentive admixture, fiber,fly ash and expansive admixture have been analyzed.