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View Full Version : Do concrete mixer trucks mix concrete?



Stephen Tashiro
05-19-2011, 10:17 PM
Is concrete that is delivered in trucks mixed and then pumped into the truck or are the unmixed dry ingredients and water put into the truck and mixed there?

Dave Lehnert
05-19-2011, 10:29 PM
They do it each way. But not with the same truck. Takes a special truck for each.

Bob Rufener
05-19-2011, 11:34 PM
Typically, the ingredients are put into the truck and mixed in the truck.

Dan Hintz
05-20-2011, 7:45 AM
Takes a special truck for each.
Really? Didn't know that... any chance you know the reason why?

Mike Henderson
05-20-2011, 9:53 AM
Really? Didn't know that... any chance you know the reason why?
I think maybe he's referring to the trucks that mix concrete on site. They're used primarily for putting in pools. They do not have a barrel but have hoppers along the truck which hold the materials and water. The proper amount of each component is metered into a tube with a screw drive and the mix is extruded out the back. Often when putting in a pool, it takes a lot of time. The concrete in a barrel mixer would set up before you got everything done.

The companies who have those trucks serve specialty markets (like pools and curbing). The concrete is more expensive than from a barrel mixer. I don't know what the proper name is for those trucks.

[Added: here's (http://en.wikipedia.org/wiki/File:Volumetric_Concrete_Mixer.jpg)a picture of one of those trucks. And here's (http://www.holessolutions.com/services/volumetric_mixers.shtml)another.]

Mike

Dan Hintz
05-20-2011, 11:54 AM
Ah, gotcha... seen those before.

Scott T Smith
05-20-2011, 6:16 PM
I think maybe he's referring to the trucks that mix concrete on site. They're used primarily for putting in pools. They do not have a barrel but have hoppers along the truck which hold the materials and water. The proper amount of each component is metered into a tube with a screw drive and the mix is extruded out the back. Often when putting in a pool, it takes a lot of time. The concrete in a barrel mixer would set up before you got everything done.

The companies who have those trucks serve specialty markets (like pools and curbing). The concrete is more expensive than from a barrel mixer. I don't know what the proper name is for those trucks.

[Added: here's (http://en.wikipedia.org/wiki/File:Volumetric_Concrete_Mixer.jpg)a picture of one of those trucks. And here's (http://www.holessolutions.com/services/volumetric_mixers.shtml)another.]

Mike


These trucks are called Concrete Mobile Units in the trade; the technical name is a concrete volumetric mixer. They are also used in urban areas for customers that want less than a full load (such as a sidewalk, patio, etc).

95% or so of concrete trucks mix the concrete in the truck from a conbination of unmixed dry ingrediants and water. The on-truck water is primarily for clean up, and if any water is requested to be added to the mix at the site (usually a bad idea because it weakens the mix).

Jim O'Dell
05-20-2011, 7:57 PM
Scott is right on with his answer. Grew up in the Ready Mix concrete business. If you see a concrete operation, you will see a conveyer belt that rock and sand ride up to a holding hopper, cement is lifted probably by screw (At my Granddad's plant the cement came in by rail), and water was added as needed. Each ingredient was loaded into the truck one at a time by weight to achieve the prescribed mix for that particular job, and the truck would have it mixed by the time they got to the job site. Grandfather was the managing partner, my Dad was the plant foreman. Grandma and Mom did the books. Me? I lit firecrackers off the truck driver's cigarettes and dropped them behind other drivers.:D:D Sure got me in a lot of trouble. :cool: Jim.

Stephen Tashiro
05-21-2011, 10:15 AM
water was added as needed

Jim,

Was the water measured in any way? - or did the person who added it just use a hose, skill and experience? In my own mixing of concrete, I find the hose reliable, but not the other two.

Karl Card
05-22-2011, 12:41 AM
That is cool.. I never knew that but then again I never was in the pool making business. The only thing I remember was that the drivers used to carry a bottle of coke with them so that if they got stuck or whatever on the way back to the shop, the coke would keep the concrete from setting up...

Dave Lehnert
05-22-2011, 4:16 PM
Yep, What he said.






I think maybe he's referring to the trucks that mix concrete on site. They're used primarily for putting in pools. They do not have a barrel but have hoppers along the truck which hold the materials and water. The proper amount of each component is metered into a tube with a screw drive and the mix is extruded out the back. Often when putting in a pool, it takes a lot of time. The concrete in a barrel mixer would set up before you got everything done.

The companies who have those trucks serve specialty markets (like pools and curbing). The concrete is more expensive than from a barrel mixer. I don't know what the proper name is for those trucks.

[Added: here's (http://en.wikipedia.org/wiki/File:Volumetric_Concrete_Mixer.jpg)a picture of one of those trucks. And here's (http://www.holessolutions.com/services/volumetric_mixers.shtml)another.]

Mike

ray hampton
05-22-2011, 5:42 PM
speaking of concrete trucks, how often do you see a cement truck with dual -wheels on the front ?