Common Situations And Repair Methods Of Inorganic Grinding Stone Edge Damage

Inorganic grinding stones (cement-based grinding stones) are widely used in floor and wall decoration due to their high hardness and good wear resistance. However, they are brittle and prone to damage at the edges due to collisions, thermal expansion and contraction, and improper construction. The following provides a detailed explanation from two aspects: common damage situations and repair methods:

1, Common damage situations of inorganic grinding stone edges
Corner cracking: When the edge is impacted by external forces (such as furniture movement or falling objects), the joint between the cement base and the aggregate cracks, forming small gaps or cracks, which is the most common type of damage.
Peeling: The surface layer (1-3mm) of the edge separates from the base layer, often due to improper treatment of the base layer (such as lack of hair or oil stains), insufficient maintenance (low strength caused by early water shortage), or long-term moisture (water penetration leading to bond failure).
Cracks: Longitudinal or transverse cracks appear at the edges, caused by thermal expansion and contraction (different expansion coefficients from adjacent materials, no expansion joints), base settlement (uneven ground, local stress concentration), or lack of construction joints.
Pores: Small holes appear at the edges, often due to uneven distribution of aggregates (locally less aggregate, more cement, shrinkage after drying) or incomplete compaction of materials during repair (air not being expelled causing pores).
2, Inorganic grinding stone edge repair method
Repair should follow the core process of "cleaning → color matching → filling → curing → polishing", and handle it according to the situation:

(1) Corner cracking (small gap, width<5mm)
Materials/tools: inorganic grinding stone repair agent (matching with the original color), angle grinder (equipped with diamond grinding disc), brush, scraper, sandpaper (240-600 mesh), water, plastic film (optional).
Steps:

Clean the damaged area: Use an angle grinder to polish the cracked edge flat, remove loose particles and floating dust, clean with a brush, and wet with water (no visible water on the surface).
Mixing repair agent: Mix repair agent (A: B components) according to the instructions, add a small amount of inorganic pigment for color adjustment (consistent with the original color of the grinding stone, and use the original grinding stone powder as an auxiliary color adjustment).
Fill the gap: Use a scraper to fill the gap with repair agent, compact it, and smooth the edge (slightly higher than the original surface, as the repair agent will shrink).
Maintenance: Cover with plastic film at room temperature (5-35 ℃) and maintain for 24-48 hours (avoiding trampling and water flushing).
Polishing: After curing, use sandpaper to polish from coarse to fine (240 grit to remove height, 600 grit to smooth), and finally use grinding stone specific polishing agent or wax to restore luster.
(2) Peeling off (surface peeling, depth>3mm)
Materials/tools: repair agent, interface agent (such as epoxy interface agent), angle grinder, brush, scraper, sandpaper.
Steps:

Cleaning the base layer: Use an angle grinder to polish the peeling area to a solid base layer (exposing the cement base), remove loose layers, clean with a brush, and wet with water.
Brushing interface agent: Apply inorganic interface agent on the polished base and peeling surface to enhance the adhesion between the repair agent and the base.
Color filling: Adjust the repair agent and fill the gaps according to the "corner cracking" steps, compact and smooth it slightly above the surface.
Maintenance polishing: After 24-48 hours of maintenance, polish with 240-600 grit sandpaper to restore luster.
(3) Crack (width<2mm)
Materials/Tools: Inorganic grout (low viscosity, high strength), angle grinder, brush, scraper, sandpaper, masking paper.
Steps:

Open V-shaped groove: Use an angle grinder to open a V-shaped groove along the crack (depth 2-3mm, width 3-5mm), remove loose particles, clean with a brush, and wet with water.
Paste decorative paper: Paste decorative paper on both sides of the crack (to prevent the repair agent from contaminating the surrounding area).
Grouting repair: Use a scraper to fill the grouting adhesive into the V-shaped groove, compact it, and smooth the surface (slightly higher than the original surface).

Maintenance polishing: After 24 hours of maintenance, tear off the decorative paper and polish it with sandpaper (240-600 mesh) to restore its luster.
(4) Hole (small hole, diameter<5mm)
Materials/tools: repair agent, angle grinder, brush, scraper, sandpaper.
Steps:

Cleaning holes: Polish the edges of the holes with an angle grinder to remove loose particles, clean with a brush, and wet with water.
Color filling: Adjust the repair agent and fill the holes according to the "corner cracking" steps, compact and smooth it slightly above the surface.
Maintenance polishing: After 24-48 hours of maintenance, polish with 240-600 grit sandpaper to restore luster.
(5) Large area damage (missing corners>5cm)
Materials/Tools: Inorganic grinding stone prefabricated blocks (matching with original color and aggregate), structural adhesive (marble adhesive), angle grinder, brush, scraper, sandpaper.
Steps:

Cleaning the base layer: Polish the damaged areas to a solid base layer, remove loose layers, clean with a brush, and wet with water.
Cutting prefabricated blocks: Cut inorganic grinding stone prefabricated blocks according to the shape of the damage (slightly larger than the damaged area, ensuring coverage).
Adhesive fixation: Apply structural adhesive (marble adhesive) on the back of the base layer and prefabricated block, compact and adjust the position (flush with the surrounding area) after pasting.
Joint polishing: After 24 hours of curing, use an angle grinder to polish the edge of the prefabricated block (seamlessly connected to the original grinding stone), and then use sandpaper (240-600 mesh) to polish it smooth and restore its luster.
3, Repair precautions
Color matching: Before repairing, take the original grinding stone powder or small pieces, mix them with the repair agent (a small amount multiple times), compare the colors of the test blocks, and then repair them extensively after they are close.
Maintenance environment: temperature 5-35 ℃, humidity<85%, avoid direct sunlight and wind (plastic film can be used to cover and moisturize).
Expansion joint treatment: After repair, check the surrounding expansion joints (width 5-10mm). If they are missing, they need to be re cut and filled with elastic sealant (such as silicone sealant) to prevent further cracking.
Daily maintenance: Avoid heavy objects hitting the edges after repair, regularly wax (every 3-6 months) to protect the surface and reduce wear and tear.
By using the above methods, the problem of inorganic grinding stone edge damage can be targeted to restore the decorative effect and functional use.