The Effect of Redispersible Polymer Powder Dosage on Mortar

With the formation of the final polymer film, a framework system composed of inorganic and organic binders is established in the cured mortar. 

The hydraulic material constitutes a brittle and rigid skeleton, while the redispersible polymer powder forms a film within the gaps, creating a flexible connection 

with the solid surface. This connection can be imagined as numerous small springs attached to a rigid skeleton. Since the tensile strength of the polymer resin film 

formed by the polymer powder is typically more than an order of magnitude higher than that of the hydraulic material, the strength of the mortar itself is enhanced, improving its cohesion.

Due to the higher flexibility and deformability of the polymer compared to the rigid structure formed by cement, the deformability of the mortar is improved significantly. 

This enhancement also disperses stress more effectively, thereby improving the crack resistance of the mortar.

As the dosage of redispersible polymer powder increases, the entire system shifts toward a more plastic state. At high dosages, the polymer phase in the cured mortar 

gradually surpasses the inorganic hydration product, resulting in a qualitative transformation of the mortar into an elastomer. In this state, the cement hydration product acts more as a "filler."

 The film formed by the dispersed redispersible polymer powder on the interface plays an additional key role by enhancing adhesion to contacting materials.

This is particularly important for challenging surfaces, such as those with extremely low water absorption or non-absorbent surfaces (e.g., smooth concrete, steel plates, 

homogeneous bricks, vitrified brick surfaces) and organic material surfaces (e.g., EPS boards, plastics). Inorganic adhesives bond to materials through mechanical embedding: 

the hydraulic slurry penetrates into the gaps of other materials, solidifies, and locks the mortar onto the material's surface. However, for difficult-to-bond surfaces, 

the mortar containing only inorganic adhesives often fails to achieve effective bonding because it cannot penetrate sufficiently into the material.

Polymers, on the other hand, bond to the surfaces of other materials through intermolecular forces, making them less reliant on surface porosity. 

While rough surfaces and increased contact areas enhance bonding strength, polymers still perform well even on smooth surfaces.

Name: Molly.Wang

E-Mail:molly.wang@jtdf-rdp.com

Mobile:+86 156 5045 0156(Whatsapp)