Make fresh mortar containing good water retention:
Cement hydration process is a relatively slow process, such as cement can not contact with water for a long time, cement will not be able to continue hydration, thus affecting the later strength development. The polymer modified mortar has higher strength than the standard value, the reason is that the redispersible polymer powder improves the water retention capacity, so that the later strength of cement increases. Secondly, the formation of small polymer phase in mortar, improve the bond strength.
Improve the workability of fresh mortar construction:
After adding redispersible polymer powder into dry mixed mortar, the workability of mortar is greatly improved, which is mainly due to the following reasons: A. When mixing redispersible polymer powder and mortar, because redispersible polymer powder particles are coated by water-soluble protective colloid, the coating layer can prevent irreversible coalescation between polymer particles so that there is lubrication effect between particles, polymer particles can be evenly dispersed in the weight of cement slurry, These dispersed particles, like ball bearings, can make mortar components flow separately and improve the workability of mortar. B. redispersible polymer powder itself contains a certain air engendering effect, redispersible polymer powder on the air induction effect should give mortar compressibility, so that mortar has good construction workability. In addition, the existence of micro bubbles also plays a rolling bearing role in the mixture so as to improve the workability of the mixture.
Redispersible polymer powder to improve the flexibility and crack resistance of mortar:
After redispersible polymer powder is added to mortar, the mortar compression ratio and tensile ratio are greatly improved, which indicates that mortar brittleness is greatly reduced, toughness is greatly improved, so that the crack resistance of mortar is improved. redispersible polymer powder in mortar dehydrating film, not only to fill the shortcomings and pores in cement stone, but also to cementhydration products and aggregate gluing to form polymer interpenetrating network, because the elastic modulus of polymer film is lower than that of mortar, so the brittleness of mortar is reduced. The mortar flexibility increases the maximum deformation limit of mortar when it is damaged, and the energy required by the defect and micro-crack propagation is absorbed to a large extent, so that mortar can bear greater stress before failure. In addition, the polymer film contains a self-stretching mechanism, and the polymer film forms a rigid skeleton in the cement hydrated mortar, which contains a movable joint effect, to ensure the elasticity and toughness of the rigid skeleton. There are pores on the surface of polymer film formed on the surface of mortar particles, and the pores are filled by mortar, which reduces the stress concentration and produces relaxation without damage under the action of external forces. The existence of high flexibility and high elasticity polymer area also improves the flexibility and elasticity of mortar.
Post time: Dec-20-2021