Concrete Sidewalk Problems: A Case Study
I was walking along a sidewalk in Bridgeport, Connecticut the other day, and I came across a series of very interesting problems with the concrete. This concrete sidewalk was subjected to far-from-ideal construction, and I came across nearly every major sidewalk issue that you could think of along the way. I’d like to share a few things I noticed…
Concrete Spalling from Poor Drainage
Concrete will show damage from spalling most obviously where water pools or runs over the concrete. This drainage line created prime conditions for spalling.
Check out how disproportionate the spalling damage (chipping and flaking of the finished surface) to this concrete slab is to the neighboring ones. While the adjoining concrete slabs seem to have relatively smooth, more attractive surfaces, this one has shown extreme spalling damage of the finished surface.
Much of this damage was dealt to the concrete over the previous winters. During this time, the city of Bridgeport has been heavily salting the roads and sidewalks. As it’s done so, the melted snow (brine) has used this gap in the curb to flow through, over the sidewalk, and downhill to the other side.
However, some of this brine has pooled on the sidewalk and soaked into the concrete itself. Nighttime tem era tu res in the sidewalk will cause this brine to refreeze. As it refreezes, the water expands, popping off the finished surface of the concrete.
Additionally, the salt from the de-icers can build up over time. De-icers are meant to be used to loosen up snow for removal later. However, to save time, many road maintenance workers will overuse the salt, hoping to melt the ice with it entirely.
These de-icing salts will soak into the concrete’s surface, and while the water evaporates, the salt is left there. Over time, it will crystallize in the pores of the concrete, and between the finished surface and the rough-faced concrete below.
Read more about concrete sidewalk repair, or check out our page on concrete de-icer protection.
Concrete Rebar Corrosion & Spalling Damage
When the rebar forms in concrete begin to rust or corrode, they expand. This expansion can lead to multiple forms of damage in the concrete, including spalling and cracking.
During my walk, I also noticed several instances of exposed rebar in the concrete. Concrete rebar is a series of metal bars that are installed within concrete slabs to help give it form and structure.
However, it’s possible — and common — for concrete rebar materials to corrode, rust, or rot when exposed to moisture. In the cases of outdoor concrete, such as are found in sidewalks, patios, and other forms, this rebar corruption is a sure thing if there is nothing protecting the concrete from moisture.
Rebar corrosion can lead to spalling in the concrete, and it can also make spalling damage much more extreme.
Rebar spalling also occurs due to expansion differences between the concrete and rebar due to temperature differences. Rebar and concrete expand and shrink at different temperatures, especially when it’s baking in the hot summer sun.
Concrete Sidewalk Repairs
This section of newly cured concrete makes it painfully obvious how badly spalled the concrete around it has been weatherworn and damaged. Without proper protection, this concrete will also be damaged soon.
As you can see in this photo, some sections of the concrete have needed to be repaired as the water, de-icer, and rebar damage caused it to deteriorate further.
The new slabs of concrete make it painfully clear how badly the rest of the sidewalk is generally damaged, spalling, and in in poor condition.
Of course, in very little time, this concrete will also become damaged by weather. Like the concrete placed there before, the concrete is susceptible to water damage that is the source of all the problems mentioned above.
Improper sidewalk construction may be good for the contractor who is called back to do repairs in the near future, but it’s going to be unnecessary costs for the town of Bridgeport.
This is an ongoing battle in progress — one that the town is going to lose.
What they should be doing is sealing the concrete after placing the slabs. By using a product such as Concrete Treat: Concrete Sealer and Blanket, they would be able to provide a concrete sealer that penetrates deep within the pores of the concrete, creating a glasslike silicate bond.
This bond would prevent moisture from making its way through the concrete, where it could freeze, leave salt deposits, or result in rebar corrosion.
To purchase Concrete Treat, check out or online store, or contact us for distributor prices. You may also contact us online, through comments to this post, or by phone with any questions you may have.