Quickrete for ballast??

[Laminarman]

I am contemplating building some concrete blocks for ballast for the top of my 6 foot dics. Is Quickrete heavy enough straight out of the bag? Or do I need to do real concrete mix to get good weight. I'm thinking of two blocks about 12" wide, 45" long and 12" high with rebar laid in them for strength, and a chain attached to the top to lift them with my loader. Any help appreciated!

 

[neilly2]

Quickrete is concrete. The only difference is the water hasn't been added.

There are only 4 basic ingredients to concrete

1. Cement
2. Fine aggregate (sand)
3. Coarse aggregate (stone)
4. Water

The differences in concrete are simply variations in the ratio of the above ingredients, which will affect the strength. (additives are only that--additions)

The bottom line is that regardless of the strength, concrete will weigh around 160 lbs per cubic foot.

There is a such thing as lightweight concrete, but Quickrete is not that.

Also, remember----it's called CONCRETE, cement is just one ingredient. One of my big pet peeves is when people say 'that's a cement sidewalk'.

 

[neilly2]

Regaring rebar:

You don't need any strength for ballast so if you were making cubes no rebar is necessary.

However, you say you want it to be 4' long so the potential for bending stress exists. Therefore, you want to put a couple of bars in the pour lenghtwise. The rule of thumb is that concrete is stong in compression but weak in tension. So, depending on how this concrete beam is supported will affect where you want to place the rebar. To cover yourself I would put four #3 bars- two at the top of the beam lengthwise and two at the bottom lengthwise. If you only put 2 bars in jump up to #4 bars. Remember that any rebar should be at least 1.5 inches away from the outside face of the concrete.

Regarding lifting chains, I would suggest casting re-bar hooks into the beam itself. I don't know if this will be clear without a picture but here goes:

Take a piece of rebar about 3' long. Bend it in half so the ends are about 4" apart. Then, take the two ends and bend than up so each end forms a hook about 1" in radius. These 1" hooks than are hooked to one of the BOTTOM bars you are setting lengthwise. The top of the bent bar should stick out of the pour a few inches and will form the lifting hook. Now, your lifting points are poured into the beam itself and hooked to the long bar. You'll be able to rig it without getting off the tractor.

This will last forever.

Take a piece of rebar about

 

[neilly2]

Just in case this hasn't been covered:

The number of a piece of rebar refers to how many 1/8s of an inch it is in diameter.

So a #3 rebar is 3/8'' in diamter and #4 is 1/2", etc.

 

[Laminarman]

Thanks Neilly2! I was thinking of the rebar for some rigidity only. It sure is cheap enough. I was simply going to put the chain over two ends of rebar during the pour and leave it out above the pour, but your way sounds more durable. The block will be supported on three sides by the heavy duty frame of the disc, and I'll simply lash it or something to the frame. I calculate these blocks will add about 1200 lbs of weight, which should be plenty enough. I may make them smaller, I don't want to crush the discs themselves. Thanks for your help everyone.