All you concrete mathematicians!

[thcri]

We have had rain every day now for over two weeks. I was forced to mow my lawn today since we did have somewhat of a break, however I put some pretty good ruts in the lawn. TC29D is a bit heavy for wetlands.

Anyway I want to make my own lawn roller and can do it out of metal culvert and fill with concrete. So what I am asking is if I take a culvert that is 72" wide and use a 12" culvert what would my weight be compared to 14" and 16" with the same width. I know doing it this way does not make it very portable but I don't care as I am not going to take it anyplace. I saw one of these built by another guy and it really does a nice job. I even love the rib marks it leaves. But mostly looking for the weight of each pipe.

Thanks in advance,
Murph

 

[Phil_R]

12" - 706 lb
14" - 961 lb
16" - 1256 lb
Specific gravity of concrete: 2.40 / 150 lb cubic foot (not 240 lb per cubic foot that I originally used /forums/images/graemlins/blush.gif )

 

[mathey]

hmmm, I get different numbers...

12" = 4.71 cf = 636-706 lbs.
14" = 6.41 cf = 865-961 lbs.
16" = 8.38 cf = 1131-1257 lbs.

the range is due to different weights of concrete I found...one site said 135 lbs/cf and another was 150 lbs/cf

 

[Henro]

At 150 lbs per cu. ft. for concrete I get:

12" = 706.5 lbs

14" = 961.6 lbs

16" = 1,256 lbs

All for a six foot length. Weight of concrete only. Add weight of pipe to get total weight... /forums/images/graemlins/smile.gif

 

[thcri]

Thanks guys,

I think I willl go with the 14". I can get the culvert for basically nothing and I have a 1-1/4" solid shaft the is 8ft long from an old air conditioner air handler. So I can make some end caps for the culvert, center the shaft and fill it all up with concrete. Get some bearings and make a frame around it and I should have a pretty good system at a pretty good price. Well at least I think so anyway.

murph

 

[Tom_H]

It depends on the mix. You can get all different kinds of concrete mixtures. There are some types of concrete that are such light density that they will float in water (presuming a waterproof sealant). There are others with 10 times the density of that. An example is the Pantheon in Rome. Finished 1926 years ago, its engineers concocted three different concrete formulas for its construction. High density for the foundation, medium density for the main structure, and ultra-light density for the dome. Your numbers allow a calculation of the volume. The independent variable you have not provided is the density of the mix you desire. Only then can you finalize the equation needed to calculate the total mass. Most common "ready-mix" formulas that you would buy at the home center will be pretty colse to Henro's 150 lb./sq. ft., though, so your final numbers would be very close to his quotes.