RDP Powder for Self Leveling Mortar

The Benefits of RDP Powder for Self Leveling Mortar

Improved Flow and Workability

- Enhanced Flow Properties: RDP significantly improves the flow properties of self-leveling mortar, making it easier to spread and level across surfaces. 

Enhanced Adhesion

- Stronger Bond with Substrates: RDP increases the adhesion of self-leveling mortar to various substrates, such as concrete, wood, or existing flooring materials. This strong bond prevents delamination and ensures the long-term durability of the flooring system.

Reduced Shrinkage and Cracking

- Mitigates Shrinkage: The addition of RDP helps to reduce shrinkage and cracking in self-leveling mortar during the curing process.

 Increased Strength and Durability

- Improved Mechanical Properties: RDP enhances the mechanical properties of self-leveling mortar, including compressive strength, flexural strength, and abrasion resistance. 

Enhanced Water Resistance

- Better Water Resistance: Self-leveling mortars modified with RDP exhibit improved water resistance, making them suitable for use in areas prone to moisture exposure, such as bathrooms and kitchens. 

Compatibility with Additives

- Versatile Additive Compatibility: RDP is compatible with a wide range of additives commonly used in self-leveling mortar formulations, such as plasticizers, accelerators, and air-entraining agents. 

Ease of Handling and Storage

- Convenient Storage: RDP is a dry powder that has a long shelf life and is easy to handle and store compared to liquid additives. 

II. Self Leveling Mortar formulation design

The baseline formulation for self-leveling mortar needs to be adjusted to the application environment (indoor/outdoor, underfloor heating system, etc.) The following is a general purpose formulation framework:

Selection Points： 

RDP products with glass transition temperature (Tg) of 0-10℃ are preferred.

It is recommended to mix aggregates with complementary particle size distribution (coarse sand: medium sand = 3:7).

Water reducing agent should be compatible with RDP to avoid flocculation.

III. Production and construction key control points

1. Production process control

Dry mixing time ≥ 5 minutes, to ensure the uniform dispersion of the powder

Ambient humidity <60% to avoid RDP pre-hydration caking.

Mixing order: add aggregate and cement first, then add additives.

2. Notes on construction

The moisture content of the substrate should be controlled at ≤4% (concrete substrate).

The deviation of mixing water quantity should be <±2%.

Ambient temperature should be within the range of 10-35℃.

Prohibit the second addition of water after the initial setting

3. Special working conditions

Underfloor heating system: it is recommended to increase the dosage of RDP to 3.5% and add 0.5% polypropylene fiber.

High load-bearing area: 10-15% steel slag powder should be added to enhance wear resistance.

IV. Diagnosis and solution of common problems

Problem 1: Surface blistering/pinhole

Cause analysis: defoamer failure, too fast mixing speed (>800rpm), insufficient base sealing

Solution:

Use two-component defoamer (silicone + mineral oil composite)

Control the mixer speed at 300-500rpm.

Pre-painting penetration type interface agent

Problem 2: Early cracking

Cause analysis: insufficient mixing of RDP, maintenance humidity <60%, poor aggregate grading

Solution:

Increase RDP to more than 2.5%.

Keep the surface moist for 72 hours by spray maintenance

Adjust aggregate fineness modulus to 2.3-2.6

Problem 3: Abnormal strength development

Cause analysis: poor adaptability of RDP and cement, excessive amount of retarding agent, too high hydration temperature.

Solution:

Conduct cement-RDP compatibility test

Adopt sodium gluconate to replace part of tartaric acid retarder.

Add 0.1% aluminum sulfate coagulant during summer construction.