Spalling concrete occurs when air and moisture are present. When carbon dioxide in concrete interacts with water, it causes steel reinforcing bars embedded in the slab to rust and expand in volume. As time passes, the expansive forces of nature cause paint to peel, crack, or break off concrete. Spalling of concrete is a serious problem that can cause injuries if the spalled concrete falls and strikes a person. The presence of spalling may also affect the structural integrity of the structure. People can report falling concrete chunks at home that could potentially injure family members.

What should you do about the spalling concrete?

Le Fong Building Services provides some examples for treating spalled concrete for building structures in commercial settings and home settings.

1. Be sure to provide enough ventilation around your home, especially in rooms that are closed up. A humid environment speeds up carbonation. Open the windows and doors of your kitchen and bathroom to reduce the humidity in these rooms.
2. It’s important to seal any cracks or holes in your ceiling and facades to prevent moisture and carbon dioxide from entering the concrete.
3. Hire a contractor like Le Fong to remove the spalled concrete until it is free from unsound materials. They can then repair it with a repair mortar like Davco Polycrete Eco.

How does the Davco Polycrete Eco work?

Davco Polycrete ECO is a premium repair mortar with high compressive strength to reinstate the integrity of the concrete slab. Davco Polycrete ECO is a two-component, polymer modified cementitious mortar which only needs mixing of the two parts as supplied, without adding water, thus eliminating any error of site mixing. Davco Polycrete ECO is an environmentally friendly repair product with lower embodied carbon footprint.

As a repair medium for concrete or cementitious surfaces damaged by chemical erosion, impact or spalling because of corrosion of reinforcement. Davco polycrete ECO can be use as bedding for the installation, patching cracks, plastering and screeding of worn concrete surfaces.

Step 1: Preparation

The repair area must be free from all unsound materials, i.e. dust, oil, grease, corrosion or any organic growth. Remove all loose materials and surface laitance. For repair of large areas, water jet or mechanical scrub the area before application.

Step 2: Primer

Prime the concrete surface with a recommended Davco Bonding Agent. Wire brush clean the reinforcement and prime with Davco 760 Reinforcement Rust Inhibitor Primer.

Step 3: Mixing

Measure and pour 80% of the volume of Part A in a clean mixing pot. Start mixer and slowly add Part B to avoid lumps. Once the mix is of uniform consistency, add the right amount of Part A to achieve the needed consistency.

Step 4: Placing

For vertical or horizontal application, apply with a trowel to achieve the right thickness (maximum thickness 30mm per layer). For repairs which need multilayer applications, it is important to ensure that previous layers are stable and well keyed, before applying the next layer.