Improvement of mortar performance by RDP

Redispersible polymer powder (RDP) is a key organic polymer additive and is widely used in dry-mixed mortar systems. After being dry-mixed with inorganic components such as cement, aggregates and fillers, it is stirred with water to form a high-performance wet mortar, which significantly improves the following key properties:

Enhanced bonding performance: RDP is redispersed in water to form a polymer emulsion, which forms a film on the surface of aggregates and substrates during the cement hydration process, significantly improving the bonding strength between mortar and various substrates such as concrete, masonry, wood, and gypsum boards. This property plays a key bonding role in tile adhesives, exterior wall insulation systems, and repair mortars, effectively preventing shedding and hollowing.

Improve flexibility and crack resistance: The polymer film formed by RDP gives the mortar excellent elasticity and deformation ability, enabling it to better adapt to micro-displacement of the substrate, buffer stress concentration, and significantly reduce the risk of cracking caused by temperature difference, substrate deformation and shrinkage. This performance is crucial for self-leveling mortar, flexible leveling layer, and exterior wall finishing layer.

Improve water retention and construction performance: RDP has a good water retention effect, reduces the rapid loss of mortar water, ensures that the cement is fully hydrated, and avoids water seepage, stratification and early cracking during construction. At the same time, it improves the workability and lubricity of the mortar, improves the leveling and compacting efficiency and surface quality, and is especially suitable for thin-layer construction.

Optimize mechanical properties: RDP works synergistically with cement hydration products to form an organic-inorganic composite structure in the hardened mortar. Although the improvement in compressive strength is limited, it can significantly enhance the flexural strength and impact resistance of the mortar, improve the durability and reliability of the overall structure, and is suitable for high-performance mortars, repair materials and floor systems.

Improve durability: The polymer film formed by RDP is hydrophobic and impermeable, effectively blocking water penetration, and significantly improving the stability and anti-powdering and peeling ability of the mortar in a humid environment. At the same time, it gives the mortar excellent anti-freeze-thaw cycle performance, ensuring its structural integrity in harsh environments (such as exterior wall insulation systems and outdoor finishing layers).

Imparting specific functions: Depending on the formulation, RDP can impart specific functional properties to mortar, such as excellent alkali resistance (adaptable to cement/lime-based systems), hydrophobicity (for waterproof mortar), self-leveling (improving fluidity), and optimized performance for the bonding/plastering layer of insulation boards (EPS/XPS).

Typical applications:

Tile adhesive: Enhances adhesion, flexibility and anti-slip properties, suitable for large-size/low water absorption tiles.

Exterior insulation system (EIFS): Improves the durability, crack resistance and impact resistance of the bonding layer and the plastering layer.

Repair mortar: Strengthens interfacial adhesion and construction convenience.

Self-leveling floor: Optimizes fluidity and crack resistance.

Waterproof mortar: Enhances waterproof and anti-seepage capabilities, suitable for humid areas (kitchens and bathrooms, etc.).

In summary, redispersible polymer powder (RDP) has become an indispensable key additive in modern building energy conservation, green construction and high-performance mortar systems by significantly improving the bonding strength, flexibility, workability, mechanical properties and long-term durability of mortar and giving it specific functionality.