Do they make a concrete mix that.... Little OT

A few questions regarding your requirements:

1. How much weight reduction are you willing to pay for?
2. What load does it need to sustain and in which dimension?
3. What are the appearance considerations?
4. Does the material need to "cure" from a slurry to a firm solid like concrete or can it already be a solid? Is the concrete-type so that it will pour into the form OR so that other things can be imbedded into it without drilling/gluing?

Here are some ideas: A. 8" o.d. steel pipe 36" long painted gray, recessed steel disk welded into each end, concrete fill in the recess flush with end of pipe. B. 8" o.d. aluminum pipe 36" long, recessed steel disks connected by

The density can be reduced in several ways:

- replace part of the concrete mix with lower-density solids

- put the concrete only at the necessary points and connect with metal/wood which may contain air spaces

- cast the concrete around a closed form within the tube creating a hollow cylinder. The form stands off the bottom on chairs used for highway mesh

Several possibilities, on commercial buildings a lightweight concrete is used for building up roof areas for proper drainage to drains. This is pumped to the roof, looks like gypsum. Gypsum floor leveler may be another option. Mortar mix with vermiculite as a filler? Never tried this , just a thought. mike

Just a suggestion.

I would look into the kind of concrete used in pouring the chimneys. It is a lightweight concrete that uses some kind of insulating, lightweight aggregrate. (pearllite?) They pour it into old chimneys to make them fire proof and stronger.

I don't know anything about it. Just saw it on TOH.

Yes there and it is commonly found at Home Depot or Lowe's. IIRC Sackrete makes Maxamizer. While still heavy typically 3, 80-90 lb. bags will cover the same area of 5 regular 80-90 lb. bags.

Maybe some info on the application would help. DAGS for lightweight concrete and you'll get a lot of alternatives.

Hey Tom.... Some great ideas.... I like your engineering mind. What I need is a wet type mix that can be poured into the size form that I mentioned..... Concrete would be perfect but would be about 100 pounds when done..... Looking for something that would have the approx strength of concrete but when done would weight maybe 50-60 pounds. No other solution will work such as pipes, wood, wire, etc. I thought that maybe their was a "plastic type" mixture that would end up weighing less.... like a concrete/plastic mix.

-Thanks for all the great thinking...

Mortar mix with vermiculite....... hmmmmmmmm Will think about that.

-thanks

Lee.... will check it out..... Thanks

..... Will goe to HD today to talk to someone.... thnx

They used to make (still do?) cinder blocks from concrete and syrofoam... I think you had to fill them with concrete after the wall was built up though...

Google for concrete canoe

One of the contests the engineering students had when I was in college ('77-'82) was building a canoe out of concrete. I saw one that wasn't successful -- concrete with small styrofoam balls as the filler. Other designs were more successful. Over 200,000 google hits. Good luck. ;-)

-- Mark

Argh... That was supposed to simply say:

"Try 'concrete canue' as the quotes help"

Concrete canoes are built using concrete with a high strength to weight ratio and often some complex reinforcement. This is a different problem than trying to find the lightest concrete. I'd think something with vermiculite or pumice as an aggregate would be a better choice. A high slump mix so the stuff doesn't float to the top.

-j

I now deem that this thread is dead..... Once we get into concrete canoes I draw the line.... LOL Thanks to all for great ideas.

They make a concrete that is mixed with Styrofoam beads. I believe it's used to insulate steam pipes. I seem to recall it took a special coating on the beads to prevent them from clumping, do I don't know if it a DIY type of thing.

That sounds like hypertuffa. :-)

Glenna

Expanding polyurethane ?