I was watching a concrete delivery yesterday and got to wondering -
what happens with the concrete that is left over in the truck? I
suppose they keep the truck turning with some extra water so it
doesn't solidify into a solid block, but then what? Does it get used
for something, or do they just have to find a place to dump it?
If the concrete is for a house being built then often times the truck
dumps the excess at the building site. At least that's what happens
here on Whidbey Island. I had to bury a bunch of concrete. And I know
plenty of folks who have done likewise. A pain in the ass.
I remember quite clearly, sometime in the 70's my brother was working
a large construction site in the MPLS area.
They had about 30 trucks inbound with concrete, and there was some
thing that went wrong with the forms, or something...
They very quickly pushed a big hole open, and dropped all 30
truckloads into it, and covered it up.
It was only a few years ago, some 40 years later, when new building
construction was started, that they "found" this enourmous monument
under a former parking lot..
It delayed the new buildign construction by a Long time... No one
seemed to know anything about this HUGE mass of of underground
concrete. Major expense! to bust it all out...
No one left to admit where it came from, or why it was there.
Anybody from the MPLS area have heard of this in the last few years?
There are two things they'll do with it. If you let them, they will dump
any excess on your property where you want. I have 20 acres, and lots of
places with low spots or potholes that need filling, so it's a benefit to
me to have them put it there.
The other thing they do is transport the remainder to a "washout" site.
Companies will pay to have the trucks come rinse out their barrels in a
pit. That leftover is mixed with a little dirt, and over-wet, then
stirred frequently enough to prevent its becoming a solid block. People
then pay to have "washout" delivered as roadbase material and fill under
new slabs. It's a superior base, that eventually hardens to about
2000psi soil-cement concrete.
With most ready-mix companies, the drivers _have_ to wash down before
they go on the road -- they're required to, to maintain the equipment.
So whether or not they dump the excess, they still need a place to wash
the chute and the face of the auger.
It's only a little bit of a mess, but you have to put up with that.
Ever see those 2' x 2' x 6' stackable concrete blocks for retaining walls
for gravel etc. The concrete companies here (southern Indiana-Kentucky area)
have forms that make those and all trucks come back to the concrete plant
and pour what they have into the mold. They are not perfect due to
different mixes etc. but they are strong and weigh about 4000# in full size.
Sometimes they make a partial block. Also if you live or work near a
concrete plant they may give you the left over concrete. We poured our
parking lot where I work this way, a little at a time. You always have to
have forms prebuilt and adjustable. Sometimes we were all out on service
calls and the office help had to pour it. :-) You will get different grades
of concrete but hey........it's cheap. One other thing, you never know when
they are coming. You never get more than 5 minutes warning. We let many a
lunch get cold to accomplish this.
Around here every cement truck driver has a brother in law who has a
driveway formed up on the sides only. Left over cement is dumped off
at BILs trailer house on the way back to the plant. Also looks like to
stop this practice the plants load every load short about 1/2 yard but
in reality it forces a truck to go back for another load, at the
I blacktopped the parking lot one place I worked with leftover
asphalt. One of our customers owned a fleet of asphalt trucks, and part
of the local plant. Some days they had a full truckloas left in the
machine and needed a place to dump it. We had to go rent a power
roller, but we saved about $5,000 and eliminated the mess from the
existing old dusty slag that was hauled from the steel mill. The
business owner was furious that we spent $75 to pave the lot. ;-)
My dad had a concrete company next door to him some years ago.
They had 20 or so acres of land that slopped towards a small river.
The trucks would beat it back and dump some water in quick. The
tank was always turning - mixing the mix. The small amount of water
with the truck would delay for a time. They would then head for the
parking lot where the trucks parked. They slowly dumped the end of
each load into the lot and wash out in another area. Park on the
other side. Over several years they worked side to side and the
rough looking - think traction - parking lot expanded down the hill.
They then started double stacking it - as some areas were light or
It was only good for them, no one wanted to buy the land under them
and kick them out. Even the beavers in the river built a dam and
didn't phase them.
A lot of auto wrecking yards and other industrial sites have paved
their lots with leftover truckloads of concrete like that - you could
do the same thing on a farm with paving the access roads. Just put
out the word to the concrete yard that you want some, and have some of
your workers ready to drop what they're doing and place and finish it
If it's for a parking area or a farm road you only need to make
temporary forms to hold it till it sets up, screed it off level and
give it a rudimentary float and jitterbug job to get the aggregate
Though it would look a lot better if you had a Power Trowel to hit it
with some hard-troweled finishing after it has an hour or two to set
up, and/or a brush finish if it's on any sort of slope. And give it a
quick coat of curing sealer with a garden sprayer.
Oh, and a bunch of traffic cones so nobody drives on the new slab till
it's had a day or two to cure.
He still had junk he bought when he got out of the Navy sitting in
the way in the shop, along with several hundred 30 year old B&W TVs that
were never picked up after they were repaired. He got mad one day when
we complained about the lack of room to work and cut an early photo
machine in half, and dragged it through a window. It didn't matter that
the supplies for the tintype photo process hadn't been available for
decades, he thought it was valuable.
He got even madder when we hit a slow week and painted the inside of
the storefront. He didn't speak to us until the end of the month, when
he realized that sales were up 30%. The business had been there over 30
years, and had never been painted. He had used 1/2" plywood for the
interior walls, and they were gray with dirt from the parking lot. We
tiled the plywood floor, changed the layout in the front and re arranged
all the inventory to make it easier & faster to do our work. His son
donated all those TVs to a vocational school, and it looked like a
different place. Business more than doubled, for an investment of under
Form up some simple, small thing off to the side someplace - patio
blocks, pavers, fenceposts (you'll need refinforcing to make those work,
normally) landscape blocks ... all the way down to bricks, and make some
good out of it. You might even be able to make a small side business out
of having the forms, and being willing to come set them up near whoever
is getting concrete poured, so they (or you) get some useful thing from
the excess, rather than a lump of crap to bury.
Boy, there sure is a lot of misinformation available here.
There are many variables in the concrete business. It is not unusual to
have a cubic yard or more of leftover concrete in the truck after the
pour. The driver has a huge obligation to clean all chutes, hopper, and
any splatter on the rear of the truck before he goes back on the street
- this has more to do with broken windshields and law suits. He dumps
whatever water he has left into the drum with the left over concrete if
there is any chance of it setting up before he gets back to the yard.
If it happens to be a yard that casts the big blocks, they will use up
the concrete making them if there is time. These blocks are 2' x 2' x
4' with tongue and groove surfaces so they can be stacked with a piece
of heavy wire rope cast in the top for a lifting eye. These blocks take
16 CF (about .6 of CY) and weigh between 2000 and 2500 #. When a yard
is really busy there is often not time to deal with these and not all
yards even make them. The driver empties the truck in a designated area
of their yard. The EPA requires that they hold the runoff water. The
left overs are junk that is not usable for anything in the concrete
business. It is usually referred to as "wash out". If you have a
parking lot or some other use for the material, they will usually sell
it far cheaper than you can even buy #57 stone. You will need your own
dump truck and make an arrangement with the yard to load.
We have sometimes received concrete so fresh we could have finished it.
There is no or very little picking and choosing. Whatever the loader
scoops up is what you get. It may have hardened lumps, etc. It is all
material that breaks fairly easy under track equipment, usually even a
backhoe. It makes a fantastic fill material and even finish road or
parking surface. Even though the cement has turned hard, it will sort
of re powder under the machines and the stuff gets really hard after
some rain and grading. It is not homogenous concrete, but it is a dense
and solid surface.