Title says it all; I’m sure a thin layer of cement will be left over after they poor it all, and I would imagine that thin layer would harden and then the next time they use the mixer another thin layer would be leftover and so on and so forth. After a while I would imagine it would accumulate to the point where it renders the mixer unusable.
Why is this not the case?
In: Engineering
All concrete is ordered and that entire order is delivered in full without exception. The left over is going on ya grass brother.
They just use a [little bit](https://youtu.be/VHhB2XoCeP4) of high explosive to break it free
Actually, cement truck mixers are like giant blenders that keep the party going by spinning! After delivery, they rinse out any leftovers with water to prevent clogging. It’s a bit like how we make sure to clean out our blenders after making a smoothie, so nothing sticks. My advice? Always clean your tools right away—it saves you from a world of hassle later on. Have you ever seen one of those mixers being cleaned? It’s oddly satisfying!
Go to a new home job site after a slab is poured. You’ll find patties of cured concrete all around. They also have on board hoses and water supply to keep everything washed out
The short answer is that most companies require the customer to provide a dumping spot for leftover concrete, because it would cause this issue if left in while they drive back. And some even require water so they can hose down the inside before it hardens.
Depending on how thick the layer becomes or how much is left, sometimes people will literally have go inside with a jackhammer and spend hours removing the hardened concrete.
Which is why these days you can order on-site concrete for smaller projects, where special trucks will mix it on demand and pump it into place.
Worked commercial construction for many years. After pouring trucks would find a spot at the site for the driver to do a thorough rinse of the truck and dump the wet slurry of leftover cement, clean the chute, hose off any that had splashed onto any part of the truck etc… then when back at the plant they can do another clean with chemicals.
I knew the guy that owned the plant. He was a real ass. Drivers would tell us they’d be in trouble if they brought back a dirty truck/didn’t clean off well enough. However they would say they’d also be in trouble if they took too long at the job site and didn’t return in time for the next load. As a result this guy’s trucks were often in pretty shitty shape with dried cement on them.
Theres a video by Veriatsium on Youtube, where the theme of the video is, how it would feeand what would happen, if you get drowned in cement. try find it, I think its still relatively new.
He states there, that usually the time is right to bring the cement to the job site and back, but when there is some bad traffic or something, the drivers of the trucks would always keep one or two bottles of Cola with them. Apperenetly some chemical in the Cola lets the cement be liquid for longer than the usually and gives them time to drive back to the job site or the their workplace.
Well the funny thing is that sometimes it does, you just break it out manually by hand with power tools and hammers. Or if you’re a crazy person explosives. Ask the Mythbusters how much explosives it takes to make a cement truck completely disappear.
They usually add retardant additives to the mix so that it doesn’t cure while in transit. In my country they have some emergency coca-cola bottles (no joke) to throw in the mix in case it takes longer for the truck to arrive to further delay curing process
You see that hose coiled up on the truck don’t you. They usually rinse the cement off the ramps and slosh a bunch around inside to prevent it from setting up. They used to dump their excess all around our neighborhood when they were building out there.
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