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Understanding and Dealing with Concrete Spalling

“Water is fluid, soft, and yielding. But water will wear away rock, which is rigid and cannot yield.” These are the words of Laozi (also known as Lao Tse), the ancient Chinese philosopher and the founder of Taoism. In his writing, the quote serves as a metaphor for how something, or someone, can be strong even in its softness.

Of course, we are not here to discuss Taoism. Laozi derived his beautiful metaphor from something very real: the ability of water to enter cracks, expand, and destroy rock surfaces. For homeowners, this natural phenomenon is a potential problem that could ruin their concrete surfaces, or surfaces made from similarly hard materials.

Another ancient Chinese philosopher, Sun Tzu, had his own advice for dealing with problems. In The Art of War, he wrote, “If you know your enemies and know yourself, you need not fear the result of a hundred battles.” In order to prevent your floors, walls, sidewalks, and patios from this kind of damage, you first need to understand how it happens. Here is some information on concrete spalling, including what exactly it is and how to prevent it.

What is Spalling?

Have you ever biked around the neighborhood on a lovely afternoon, only to get slightly or even completely tripped up by a crack-riddled sidewalk? Did the sidewalk appear to have cracks, fissures, or even pits forming on the surface? If so, then you have witnessed firsthand the effects of spalling, a thorn in the side of anyone who treads on concrete ground.

Robson Forensic describes spalling as “flakes of material that are broken off of a larger solid body.” In this case, the solid body is the concrete, whether it is a block in the chain that comprises a sidewalk or a larger mass dug into the earth to make a backyard patio. The flakes of concrete may not always be visible, but their absence creates the telltale marks that you can identify as a spalling problem.

A few cracks alone may not seem like a big deal. However, what you can see on the surface may be a symptom, indicating more severe damage in the interior of the concrete. Most concrete works include reinforcing bars (rebars) of steel, which can rust if exposed to water and air. The rust can cause the rebar to expand, potentially giving way to a breakdown in the whole foundation.

What are the Common Causes?

Elizabeth Weinstraub, writing for The Balance, describes spalling as “the result of water entering brick, concrete, or natural stone.” A wrinkle to this fact is that water, along with cement and a rocky “aggregate,” is required to create the material we call concrete. The mix requires a delicate balance, and too much water can cause trouble right from the beginning. Fresh concrete may have spalling in its future if it endures stormy weather in the period when it needs to dry.

Most professional contractors take the weekly forecast into consideration when picking a date to lay out the mix. Unfortunately, as ConcreteToolReviews.com warns, some may be a bit too hasty in completing the job. Before they “start the finishing process,” they need to let the “bleed water” emerge from the interior to the surface and evaporate. Applying the finish beforehand will block it from escaping, and it will give the rebar plenty of company.

Even after the concrete hardens, water can still reach the rebar and leave room for air. People in warmer climates must protect their surfaces from humidity, that rust-inducing mix of water and air. Those who live in colder climates must instead deal with the effects of constant freezing and thawing — plus the unintended consequences of salting them.

How to Prevent Spalling

Spalling is a potentially costly and even dangerous problem, no matter the cause. Knowing the cause, however, can help you figure out the best way to treat it. If you are handling the installation yourself, such as in your backyard or front yard, then you need to get the mix just right. The correct water-cement ratio may vary depending on the exact materials you use, so be careful.

Patience is valuable during the process of installing concrete. Given the unfortunate effects of inclement conditions, you may need to wait until a string of good-looking days before pouring the mix. Even when it begins to dry, give the bleed water time to exit the surface. Only then can you apply the finish and consider the job done.

Even if you do the initial set-up well, freeze-thaw conditions may be a recurring threat to your concrete each winter. Anyone expecting to deal with such weather may want to order air-entrained concrete. This type comes with “billions of microscopic air cells per cubic foot,” giving any water within the concrete a bit of room for expansion upon freezing.

If none of these measures are enough to prevent flaking and cracking, you do not need to give up on your concrete just yet. Surface-level touch-ups and patches can handle relatively minor concerns. Larger-scale problems could still be repaired with the right tools and methods. Making a mistake is not the end of the world.

Using Concrete Sealer for Spalling

Arguably the best way to prevent concrete spalling is the application of a high-quality concrete sealer. Concrete is more porous than many may believe from such a hard material. A product like this can protect it from the elements, as well as sidewalk salt and other materials you may use for cleaning or thawing. As such, it is a must-have for anyone who has or plans to have a concrete surface of some kind on their property.

Conselcor is the home of StableCrete Concrete Sealer, a top-notch, non-toxic, eco-friendly, all-in-one protectant. It is designed to penetrate and fill any fissures, no matter how small, effectively waterproofing and strengthening the concrete. “Fluid and soft” in its own way, it forces anything that touches the surface to yield. You can order StableCrete Concrete Sealer from us right away and stall any spalling in the future.

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