Common Factors And Repair Methods For Color Fading Of Terrazzo Prefabricated Panels

Common factors and repair methods for color fading of terrazzo prefabricated panels
Terrazzo prefabricated panels are widely used for floor and wall decoration due to their beauty and durability, but they are prone to color fading after long-term use. The following is a systematic analysis from two aspects: common factors and repair methods, to help solve the problem of fading.

1, Common factors causing color fading of terrazzo prefabricated panels
(1) Material quality factors
Poor weather resistance of aggregates and pigments
Pigments: If ordinary organic pigments (such as azo compounds) are used, they are resistant to ultraviolet radiation, have weak oxidation ability, and are prone to decomposition and fading after long-term exposure (especially red and yellow pigments); Inorganic pigments such as iron oxide red and chrome yellow have better weather resistance, but if the quality is not up to standard, they will still fade.
Aggregates: Low hardness stones (such as some limestone fragments) are prone to wear and tear, causing surface aggregates to peel off or darken, resulting in lighter colors; High hardness aggregates such as glass and quartz are more stable.
Cement substrate issue
Low cement grade or the addition of inferior additives (such as excessive water reducing agents) can affect the complete hydration of cement, resulting in uneven base color and easy fading in the later stage (such as poor quality white cement that tends to turn yellow).
(2) Construction process factors
Inadequate maintenance
After the prefabricated board is formed, the early maintenance (covering moisture and temperature control) is insufficient, the cement hydration is not sufficient, and the surface is loose and white; Rapid evaporation of water during maintenance can also cause shrinkage cracks and accelerate color deterioration.
Grinding and polishing defects
Improper selection of polishing mesh (such as rough grinding without fine grinding) or uneven polishing, resulting in inconsistent surface glossiness and varying visual color depth; Grinding too deeply exposes cement that has not fully hydrated in the lower layer, resulting in a gray color.
Construction pollution residue
During the laying process, the cement slurry and adhesive were not cleaned thoroughly, which later reacted with air and moisture to form stains (such as yellow spots), masking the original color.
(3) Environmental factors for use
ultraviolet irradiation
Outdoor or strong light environments (such as sunrooms), ultraviolet radiation damages the molecular structure of pigments, and organic pigments are prone to fading; Iron ions in cement oxidize under light, causing white terrazzo to turn yellow.
Acid alkali corrosion
Strong acids (such as hydrochloric acid), strong alkalis (such as sodium hydroxide), or chlorine containing cleaning agents corrode the structure of cement paste, damaging the bond between pigments and cement, resulting in color loss and lightening; Acidic substances react with calcium carbonate in cement to form soluble salts, accelerating surface peeling.
friction and wear
Frequent friction between people, vehicles, etc. results in the wear of the surface cement slurry, exposing the aggregate and the lighter colored cement base underneath, causing visual fading (such as the gray color of terrazzo edges in public areas).

Water infiltration and carbonization
Long term water accumulation (such as in bathrooms and balconies) causes water infiltration, and the calcium hydroxide in cement reacts with carbon dioxide (carbonation) to produce calcium carbonate, which changes color from dark to gray; Water carries pollutants (such as rust and oil stains) that infiltrate and form color spots.
(4) Maintenance management factors
Improper cleaning method
Frequent cleaning with a hard brush (such as steel wire balls) and highly corrosive cleaning agents can damage the surface protective layer (such as sealants and wax) and accelerate color loss; Failure to dry in a timely manner after cleaning resulted in local carbonization and stains due to water residue.
Protection layer failure
Failure to apply or apply sealant or wax for a long time, resulting in the loss of waterproof, stain resistant, and UV resistant properties on the surface; Poor quality protective agents (such as low weather resistant wax) are prone to aging and peeling, and cannot provide sustained protection.
2, Repair method for color fading of terrazzo prefabricated board
(1) Preventive measures (when laying new prefabricated panels)
Material selection
Aggregates and pigments: Priority should be given to inorganic pigments with good weather resistance (such as iron oxide red, chrome yellow) or high-performance organic pigments (with a light resistance level of ≥ 7); High hardness and weather resistant quartz and granite fragments are used as aggregates.
Cement and admixtures: Use Portland cement or white cement with a grade of ≥ 42.5 (choose pure white cement for white terrazzo); Choose products from reputable manufacturers for additives and avoid excessive use (such as water reducing agents with a dosage of ≤ 1%).
Construction specifications
Maintenance: After molding, cover with wet burlap bags or plastic film, maintain a humidity of ≥ 90%, and maintain for ≥ 7 days (insulation is required in winter); Continue watering and curing for 3-5 days after demoulding to avoid shrinkage cracks.
Polishing and Grinding: There are multiple processes including rough grinding (60-120 mesh), medium grinding (240-400 mesh), fine grinding (800-1500 mesh), and polishing (over 3000 mesh) to ensure a smooth surface and uniform gloss; Clean the dust after polishing to avoid contamination.
Sealing treatment: Immediately apply water-based penetrating sealant (such as silane) or wax (choose weather resistant floor wax) after polishing to form a protective film that blocks water, acid, alkali, and ultraviolet rays.
Adaptation to the usage environment
Outdoor or heavily illuminated areas: prioritize using inorganic pigment terrazzo or applying UV absorbers; Regularly (every six months) apply sealant.
Acid alkali environment (such as laboratory, kitchen): Waterproof layer should be applied to the floor, and neutral cleaning agent (pH 6-8) should be used for cleaning.
(2) Remedial measures (faded prefabricated panels)
Mild fading (surface contamination, protective layer failure)
Cleaning and stain removal: Use neutral cleaning agents (such as dishwashing detergent) in combination with a soft bristled brush to remove oil stains and yellow spots; Stubborn stains (such as rust) should be lightly wiped with oxalic acid solution (5% -10%), and immediately rinsed with clean water (to avoid acid residue).
Polishing: Gently polish the surface with 120-400 grit sandpaper to remove oxide layers and stains; Then grind it finely with 800-1500 mesh to restore its luster; After polishing, apply penetrant dye (matching the original color), add color, and finally apply sealant or wax.
Moderate fading (lighter color, localized wear)
Permeation dyeing: Choose a water-based penetrant dye (with good compatibility with terrazzo substrate), apply it evenly with a sponge or roller, penetrate into the cement pores, and add color; After staining, let it stand for 24 hours to fix the color.
Partial repair: For severely worn areas (such as corners), fill them with the same color terrazzo repair paste (containing aggregates, pigments, and cement), scrape them flat, and polish them to match the original color of the board.
Severe fading (extensive graying of color, structural damage)
Overall renovation: remove old prefabricated panels, clean the base layer (flat, clean, and free of oil stains); Re lay new terrazzo (select qualified materials, standardize construction), and perform sealing treatment after curing.

Surface coverage: If removal is difficult, a thin layer of terrazzo veneer (terrazzo stone slab) can be laid on the surface of the original board, fixed with adhesive, and the edges sealed to achieve color renewal.
(3) Maintenance after repair
Regularly (every 1-2 months) clean with a soft bristled brush or vacuum cleaner, avoiding hard brushing; Clean and dry to prevent water residue.
Apply sealant or wax every six months to maintain the integrity of the protective layer; Inspect the outdoor area quarterly and promptly address any localized fading.
3, Summary
The color fading of terrazzo prefabricated panels needs to be managed throughout the entire cycle of "materials construction use maintenance", with prevention as the main focus (selecting weather resistant materials, standardized construction, and adapting to the environment), and repair as a supplement (mild cleaning and dyeing, moderate repair, and severe refurbishment). Through scientific maintenance, the color stability of terrazzo can be effectively extended and the decorative effect can be maintained.