Why do sidewalks have blocks, instead of being solid?
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A few key reasons:
– Helps keep concrete from cracking due to weather/temp changes
– Helps with drainage of water after rain or snow melt for better traction
– Makes it more cost effective to fix/replace squares as needed when they do crack or need to get ripped up for running utilities under.
Ground shifts, freezing water has a place to expand, pouring concrete in smaller sections is easier than doing long continuous sections, and you can replace a block without having to redo a huge section or patching and trying to get it to match.
Also, keeping large amounts of concrete from hardening is a hell of a lot more work than mixing it in a bucket or wheelbarrow when you need it.
Like concrete? They are not typically poured as separate blocks. They are joints, tooled or cut purposely as weak spots that will encourage cracks at that joint instead of random spots. If concrete is poured next to existing concrete or asphalt, they will install expansion joints between the new slab and existing medium which is separate.
Because using pre made tiles and blocks is much easier and cheaper than bringing a cement truck to pour out a massive single piece of concrete to make a sidewalk, especially considering that sidewalks often have to follow the curvature of the road or the ground. Also there’s many utilities underneath sidewalks, like power lines and water drains, which need access points. You can have access points much more easily if you haven’t poured solid concrete over everything.
We build them that way so that the cracks that WILL form, will form in a controlled way that causes the least structural damage.
I’ve worked concrete, and my first time on the job one of the old guys said “There’s only two things I know about concrete. It will get hard. And it will crack.”
And he’s absolutely right. Concrete will always, always crack. But by doing things like putting those grooves in it, we can control where and how they crack. And doing it that way we can at least make sure you always have a flat surface to walk on.
The larger the block of concrete, the greater chance that it’s going to crack due to thermal expansion. You can either pour out a long strip and let it crack where it cracks, because it WILL crack… Or, you pour the sidewalks in small blocks and put little spacers between them.
Who knew? Sidewalks are like yoga enthusiasts, always stretching to avoid the cracks!
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