Technical Specifications for Mosaic Arabesque Care
The article "Technical Specifications for Mosaic Arabesque Care", published by the China Marble Mosaic Association, defines marble mosaic re-alkali as the process where soluble salt-alkali is absorbed or migrates through the pores of the mosaic arabesque to the surface of the marble mosaic, crystallizing into white patterns or mottling.
Characteristics of Saline Spots
1. Appearance & Shape:
- Mainly white patterns or variegated spots appearing in pieces.
2. Solubility & Hardness:
- Easily soluble in water.
- Low hardness, can be wiped off with a damp cloth.
3. Recurrence & Moisture Absorption:
- Tends to reappear, especially in areas with moisture absorption sites.
- More frequent when the weather becomes dry after a damp period.
Chemical Components:
- Mainly composed of sodium and potassium salts, such as sodium carbonate, sodium sulfate, and sodium hydroxide.
- These salts easily migrate to the surface of the marble mosaic with capillary water and crystallize.
Causes of Salt-Alkali Spots
1. Alkaline Components in Cement:
- Cement contains alkaline substances such as sodium hydroxide, potassium hydroxide, and sodium carbonate.
- Water from various sources (cleaning water, grinding water, groundwater) causes the cement underneath to become wet.
- As moisture evaporates, capillary action brings these alkaline components to the surface through the micropores or joints of the marble mosaic, forming pattern-like salt-alkali spots.
2. Alkaline Components in Marble:
- Some marble types naturally contain alkaline substances (e.g., certain beige marbles).
- Even without wet installation, exposure to humid air can trigger salt-alkali precipitation, leading to salt-alkali spots.
3. External Environmental Factors:
- In saline-alkali regions, soluble salts such as sodium sulfate and sodium carbonate can migrate upwards along building walls with moisture.
- This causes white salt-alkali deposits on the mosaic arabesque surface, particularly in building corners.
4. Coastal Influence:
- In coastal areas, sea breeze carrying seawater mist deposits sea salt (sodium chloride) on the outer wall surfaces.
- This leads to the formation of white salt-alkali spots on mosaic arabesque tiles.
5. Seasonal Salt-Alkali Formation:
- During the rainy season, increased humidity can cause dampness in mosaic arabesque tiles.
- Even marble mosaics that do not usually return to alkali may exhibit alkali reappearance during this period.
How to Prevent & Address Marble Mosaic Alkali Reappearance
1. Use Protective Agents Before Installation:
- Select the right protective agent based on the type and characteristics of the marble mosaic.
- Lime-based metamorphic rock mosaics require anti-alkali protective agents.
2. Proper Protection During Wet Installation:
- Ensure bottom surface protection of the marble mosaic, even if waterproof adhesive is used.
- If marble is cut on-site, seal cut sections with waterproofing agents.
3. Avoid Strong Alkaline Protective Agents:
- Carbonate-based marble mosaics, especially porous ones, should not be treated with strong alkaline protective agents (e.g., sodium methyl silicate).
- Instead, opt for weak alkaline, eco-friendly, water-soluble protective agents.
4. Clean & Dry Before Applying Protection:
- Ensure the mosaic arabesque tile is completely dry and clean before applying protection.
- Newly cut marble mosaics should be left to dry for at least 4 days at room temperature before protection.
- No residual moisture should remain in the marble.
5. Apply Protective Agents Evenly:
- The amount of protective agent used should be adjusted based on the water absorption rate of the specific mosaic arabesque tile.
- Application must be evenly saturated for effective results.
By following these technical specifications and preventive measures, the longevity and beauty of mosaic arabesque tiles can be preserved while minimizing salt-alkali-related issues.
