Concrete Spalling: Top 3 Causes

What is concrete spalling?

Concrete spalling is the breakdown of concrete due to the natural process of weathering or chemical reactions that results in sections of cement chipping off of the main body, resulting in a fractured, compromised structure. It is the disruption of the exterior of the concrete, which then spreads to the top coatings of reinforcing steel.

Also known as "scaling," it is a common problem where the surface of the body peels, breaks, and chips away, which makes the surface highly susceptible to damage. Spalls can be 15 cm in diameter and 2.5 cm in depth.

But don't worry; spalling concrete repair products are always on hand to save the day. But before reaching that stage, why not go through the causes to prevent future occurrences?

Causes of concrete spalling 

1. Corrosion of steel and other embedded materials

Steel is not naturally occurring and, hence, is not immune to corrosion. The occurrence of corrosion in steel and other embedded metals is the leading cause of deterioration in concrete. The breakdown of steel results in its oxidation, which leads to rusting. The resulting material (the rust) has a larger volume than the surface it forms on, which is steel. This further leads to expansion, which creates tensile stress in the concrete, eventually leading to the cracking and spalling of the concrete.

2. The process of carbonation

The process of carbonation takes place when carbon dioxide dissolves in water or any aqueous solution under everyday conditions. Carbonation also refers to the formation of insoluble calcium carbonate as a result of the chemical reaction between calcium hydroxide and carbon dioxide.

This is a slow process as it occurs when carbon dioxide from the surrounding air seeps into the concrete and counters with the hydroxide (especially of calcium) to form carbonates. As a result, if the spalling has occurred after fifty years, it is due to the process mentioned above of carbonation. 

3. The Deterioration of the Freeze-Thaw Cycle

The freeze-thaw process is when water expands by nine per cent when it freezes. It is a property unique to water and is pretty common where temperatures reach below freezing at night and ascend during the daytime. The most deteriorative freeze-thaw process happens in highly saturated environments where excess water is present.

Since water is one of the three constituents of concrete's makeup, it plays a role in causing the spalling of concrete as well. When the water in the concrete freezes, it produces pressure in the capillaries and pores of the concrete. If this pressure crosses the tensile limit of the concrete, the cavity will expand and breakage will occur.

Conclusion

There are many ways in which the prevention and repair of concrete spalling can take place. You can assure that the mixing of the ingredients is done properly. You can take out and replace the entire slab if the damage is done. Spalling concrete repair products can be found in stores or ordered online to help repair surface cracks and chippings. Check out the link below to get those nuisances covered: https://www.maxkote.co.uk/