Five concrete slab problems that make you want to replace it with new concrete... But should you?
Did you know that concrete makes up almost 60% of the revenue for the entire construction industry? However, of all of that concrete revenue, over half is spent on it’s repair and maintenance.
While it is nice to have a freshly poured, brand new slab of concrete, it may not be practical for your situation, and it may be cheaper to repair what you
already have.
So... repair? Or replace?
Five common concrete slab problems that can be repaired instead of replaced:
1. Cracks
Every concrete floor has cracks. And yes, you read that correctly. Concrete is made of 4 basic
ingredients; water, cement paste (Portland), sand and stones. When the cement
“batter” is poured and placed, the water used to mix the ingredients will evaporate,
which makes the concrete shrink. When the concrete shrinks, it is a solid mass that
will naturally crack.
In order for the cracks to be “hidden,” score lines (joints) are cut into the
surface to control where those cracks will occur. These are called control joints.
So, why do we have random cracks? There are a number of factors that cause cracking.
Here are the three main types of cracks and how they are caused:
Shrinkage Cracks:
This happens when there are not enough control joints, they are not spaced correctly, they are not deep enough, or the weather during placement caused it to dry too fast (This gets deeper into engineered requirements based on water to cement ratio, slab thickness, temperature, ad- mixtures, and timing).
Structural Cracks:
These cracks result from overloading, poor structural design, sub-slab stabilization issues, concrete curl, or inadequate reinforcement. They are typically deeper and more serious, affecting the overall stability of the structure.
Crazing Cracks:
These are fine, surface cracks that resemble a spider web. They are often caused by rapid drying of the surface layer during curing.
2. Spalled Joints
This is often seen when one side of a joint is blown out, has major signs of abrasion,
or has a look of wear and tear along the length of the joint. It is also often
accompanied by the annoying 'thump thump' when a forklift or pallet jack runs
across it.
In more severe cases, one side is much higher than the other and they
damage forklift tires, cause a major slow-down in material handling, damage
finished products, safety concerns, re-route traffic patterns, and they never
get better with age.
Spalled joints are commonly caused by stabilization issues, compaction issues, mix design, inadequate joint design, curl, moisture, and more. All flooring joints should be perfectly smooth and flat causing no friction or interruptions when wheels are rolled across them.
3. Rocking Slab
Rocking slabs are found, and mutually despised, by all forklift drivers. And you've probably experienced a similar feeling walking on uneven bricks and even some sidewalk slabs.
Rocking slabs are a panel of concrete that will rock back and forth as the weighted load rolls over the slab and are usually accompanied by spalled joints and structural cracking. This is most commonly caused by concrete curl along with sub slab stabilization concerns.
4. Surface Pitting
Have you ever walked across a concrete floor that looks like someone used it for target practice with their shotgun? Yeah, we see this all the time, especially in the northern “snow belt” territory.
De-icing salt is great to melt snow and makes for a much safer walking surface, but to unprotected concrete, it is extremely corrosive. We also see surface pitting often in forklift charging areas where batteries spill sulfuric acid and it eats the concrete from the top down.
5. Corrosion
We won't take you down a science lesson of elements, metals, and their corrosion effects, but to summarize... All metals, except for gold and platinum, are unstable and will corrode. Reinforcing steel is made primarily of iron and is quick to corrode with high levels of sodium chloride, atmospheric CO2, and unbalanced pH. If the reinforcing steel within the joints corrodes, it can expand and exert pressure on the surrounding concrete, leading to spalling.
Contact us today to schedule your repair project.
Untreated concrete slab problems can lead to a whole host of other issues down the road including; interrupted work flow, inaccessibility, slower production, and a higher concern for workplace safety. And concrete problems surely don't get any better with age.
The good news is, a few cracks here and there don't warrant needing a whole new slab pour, and many of these problems are easy to repair. Contact us today to schedule a free consultation and we'll work with you to find the best repair solutions for your facility!
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