Why do sidewalks have blocks, instead of being solid?
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Easier construction, and then the squares can expand and contract with the ambient temperature without breaking as much.
The ground underneath concrete tends to shift and move depending on the weather.
Having separate tiles allows them to move, expanding and contracting. Without that the tiles would crack and break very quickly resulting in an uneven and dangerous surface.
If a tile breaks it can also be replaced without needing to replace the entire side walk.
Roads suffer from this as well, but the underlay is better prepared so that this effect isn’t as bad. They don’t often do that for sidewalks because it costs a lot more.
Bunch of reasons.
Ease. Sidewalks are usually too small for large cement or asphalt trucks to drive across and work on. Stones can be laid no matter the size of the path.
Practicality. Water, power and gas lines usually run beneath sidewalks. If there’s an issue or they need access for some reason, it’s easier and cheaper to take out stones than it is to break apart asphalt or cement and then redo it.
Aesthetic. Many people prefer the look of stones to a single solid slab.
Sidewalks also don’t need the durability of roads, since there are no cars driving over them. At least not as much or as fast.
Sidewalks flex, get pushed around by trees, crack, and need to be replaced. If the sidewalk was solid for the whole city block and it got a bad crack halfway down, you’d have to either replace the entire thing at once or cut into the existing concrete to replace a smaller section, like a “block.” But since they already do blocks, they can only replace the damaged or heaved parts of the sidewalk.
They replaced our sidewalk last month and they only did the damaged bits. They’re not planning to revisit the sidewalk on our street for 15 years. The ones that are fine, flat, and not cracked or damaged they didn’t replace, saving us money.
In my area the sidewalk is about 300-400 feet long and was all replaced a couple of years ago. They put groves in it about every 4-6 feet so that if it settles or a tree root or freezing temperature pushed it up it will crack along the grooves made in it. Also if a piece needs to be removed to do other work underground like water, gas, electrical they can easily cut at the grooves made when first pouring it without doing the whole block.
Concrete roads usually have the same grooves but are usually 10-20 ft apart.
Concrete sometimes breaks when being cut and this way you only replace 6-10 feet for repairs instead of the whole side of the street.
Most sidewalks are concrete, a material made by casting it in molds. This causes it to be done in sections, because you generally don’t have a single model large enough to fill the full length of the sidewalk at once or a big enough truck to make it all one big block.
This also gives the advantage that you can leave a little gap between segments, called an expansion joint, that allows the different segments to settle, expand and contract separately.
Worth pointing out this is almost only in the US and Canada.
So one big reason is that walking is very under prioritized compared to most of the rest of the world.
A large single block of concrete will experience more stress from changes in the ground around it. The ground settles, freezes, tree roots grow, etc. It’s a guarantee that it will crack.
By pouring the concrete in blocks with a small gap, you give it room to flex. The gaps are literally called “expansion joints”.
If you didn’t include these intentional cracks when pouring, the concrete will create cracks for you. They’ll be uglier and far less uniform than the nice intentional straight ones.
The blocks are easier to build and maintain and look better. But they can’t withstand the force of vehicles driving over them every day, that’s why streets are solid.
They are solid. Concrete sidewalks are poured all at once. What you see as blocks are actually control joints. When finishing concrete, groves are places at regular intervals so when the concrete moves, and it will move being exposed to nature and just sitting on the ground, it will crack at these joints. With out them, concrete would crack randomly.
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