What is Popout? (Surface Defects)

What is Popout? (Surface Defects Explained)

Popout is a surface defect that occurs when a porous rock inside the concrete absorbs water, freezes, and expands, popping a cone-shaped piece of the surface off. Understanding popouts helps you understand concrete surface defects and how to prevent them.

What is Popout?

Popout is:

• Surface defect: Small pieces of surface break off
• Cone-shaped: Creates cone-shaped holes
• Caused by aggregate: Porous rocks inside concrete
• Freeze-thaw related: Happens in freeze-thaw cycles

How Popouts Form

The popout process:

1. Porous rock in concrete: Porous aggregate is in the mix
2. Absorbs water: Porous rock absorbs water
3. Water freezes: Water inside rock freezes
4. Expands: Ice expands (water expands 9% when frozen)
5. Pops surface: Expansion forces surface to break off

What Causes Popouts

Popouts are caused by:

• Porous aggregate: Rocks that absorb water
• Freeze-thaw cycles: Temperature cycles that freeze water
• Water exposure: Concrete exposed to water

How to Prevent Popouts

Prevent popouts by:

• Quality aggregate: Use non-porous, quality aggregate
• Proper mix design: Avoid porous rocks in mix
• Sealing: Seal concrete to prevent water entry
• Quality control: Screen aggregate before use

How to Repair Popouts

To repair popouts:

1. Clean hole: Remove loose material
2. Fill with patch: Use appropriate patching material
3. Match texture: Match surrounding texture
4. Seal if needed: Apply sealer to prevent recurrence

The Bottom Line

Popout is a surface defect that occurs when a porous rock inside the concrete absorbs water, freezes, and expands, popping a cone-shaped piece of the surface off. It's caused by porous aggregate in freeze-thaw conditions. Prevent popouts by using quality, non-porous aggregate and proper mix design. Repair popouts by cleaning and patching holes.

Have popout problems? Contact Local Concrete Contractor. We use quality aggregate and proper mix designs to prevent surface defects.