According to the standard JC/T 547-2017 for ceramic tile adhesives, the tensile bond strength after freeze-thaw cycling must meet the following requirements:
- C1-type tile adhesive: ≥ 0.5 MPa
- C2-type tile adhesive: ≥ 1.0 MPa
Testing Method
- Sample Preparation
- Apply approximately 1 mm of adhesive to the back of the tile using a straight-edge trowel before placing the tile.
- Prior to the 25 freeze-thaw cycles, cure the specimens under Standard Condition 1 (temperature: 23±2°C, relative humidity: 50±5%, air circulation < 0.2 m/s) for 7 days, followed by 21 days of water immersion.
2. Freeze-Thaw Cycle Procedure
- ① Remove specimens from water and cool to -15±3°C within 2h±20min.
- ② Maintain at -15±3°C for 2h±20min.
- ③ Immerse specimens in water at 20±3°C, allowing them to warm to 15±3°C. Hold at this temperature for at least 2h before the next cycle.
- ④ Repeat for a total of 25 cycles.
3. Post-Testing Evaluation
- After completing the cycles, store specimens under Standard Condition 1.
- Attach the pull-head to the tile and measure the tensile bond strength within 24h at a loading rate of 250±50 N/s.
Recommended Solutions to Enhance Freeze-Thaw Resistance
- Use of Water-Reducing Agents
- Helps decrease water demand in the system, improving density.
- Reduced water content minimizes the risk of cracking caused by ice expansion, thereby preserving strength.
2. Optimization of Aggregate Ratio
- Adjust the sand-to-powder ratio appropriately.
- Use well-graded aggregates to reduce void content and lower water absorption in the mortar.
: How to Improve Freeze-Thaw Resistance？){kind=link}