# What mix should I use for the strongest possible conrete?



## c.c.co. (Nov 13, 2006)

This is not for a jobsite but for making atlas balls. These balls are used for strength training and get dropped a lot and sometimes on hard surfaces. I plan on adding fiber but what mix do you guys recommend for a very strong and hard atlas ball? A premixed conrete like maximizer with some extra portland?


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## Tscarborough (Feb 25, 2006)

Mild steel or cast iron?


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## jgray152 (Oct 4, 2009)

I can't say I know everything about concrete but when I build my retainer walls, I use strictly portland cement and sand. When I order it I order a 9-10 sack mix and this concrete, after 7 days of curing, is extremely strong! I couldn't tell you what the exact ratio is from the concrete companies since they keep that a well kept secrete for some darn reason. All I can say is possibly using a 1:1 ratio of clean sand and portland, you should be close. This is what I use when I have to mix my own mix. (This home made mix has not been core tested)

There was a guy that took a core sample of the same type of mix from a redi-mixed company (not from my walls) and it cored out at around 10,000 PSI from what I hear. I was not there personally nor did I see the core sample sheet but that's what I was told.

Using an 18lb sledge hammer is whole lot of work when trying to break 4" of concrete that has been undermined using this mix. Its not lightweight by any means and is very strong. 

I hope this helps you get pointed in the right direction if not answering you question exactly.

The main trick when wanting very strong concrete is to mix it VERY DRY! 
Here is a video that I helped with from StoneMakers Artisans. A couple parts in this video you can see how try the mix is. In fact, it was slightly to wet for what we do, but this is roughly how dry you want your mix. In fact dryer would be better.

I have heard mixed comments about fibers in concrete, whether or not that actually help the strength of concrete. I would not add fibers to a ball of concrete. 

What would the diameter of these balls be?


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## genecarp (Mar 16, 2008)

Extra portland will weaken the concrete, just use sakrete crack resistant it is about 5000psi. how do you plan on forming the balls?


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## c.c.co. (Nov 13, 2006)

Those are some conflicting opinions. Diameter is something like 16 or 20". My buddy ordered some molds for making the atlas balls.


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## jgray152 (Oct 4, 2009)

> Those are some conflicting opinions.


No conflicting opinions I see. Portland does not add strength, sand and aggregate add strength. Sakrete or another brand of high strength concrete should work well. Just make sure not to add to much water as that will weaken the concrete.


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## genecarp (Mar 16, 2008)

jgray152 said:


> No conflicting opinions I see. Portland does not add strength, sand and aggregate add strength. Sakrete or another brand of high strength concrete should work well. Just make sure not to add to much water as that will weaken the concrete.


 
Im with you J, keep the water content low, use counterflow, a plastisizer to keep the concrete flowing with low water. G


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## Tscarborough (Feb 25, 2006)

So you plan on making 186# to 360# concrete balls to train with? I would certainly plan on them hitting the ground frequently, as well as breaking off various body parts.


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## shanekw1 (Mar 20, 2008)

Tscarborough said:


> So you plan on making 186# to 360# concrete balls to train with? I would certainly plan on them hitting the ground frequently, *as well as breaking off various body parts*.


:laughing:


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## jgray152 (Oct 4, 2009)

> Im with you J, keep the water content low, use counterflow, a plastisizer to keep the concrete flowing with low water. G


Probably may not even need counterflow since he is only making balls. I would imagine that as long as you fill the mold little by little, packing it as you go to reduce trapped air bubbles, you should be good.


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## concretemasonry (Dec 1, 2006)

The manufacture and quality of the molds will be important.

How you cn fill them is also very important.

As little water as possible, gradation control and variable vibration on a table and being able to change the orientation while compacting will be a big plus. You may have a "nub" left at the filling point that will have to be ground off.

If you do not account for the settlement and compaction if you want maximum strength. Under controlled conditions, you should be able to get 8,000 - 10,000 psi with the right aggregate gradation. If you just pour a typical wet mix, it wet, you will only get 3000 to 5000 psi, no matter what "goop" you dump in.


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## CJKarl (Nov 21, 2006)

Add aggregate to non-shrink grout. That's what I would do.


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## user50444 (Jul 25, 2009)

I like the steel idea + with a rubber like coating or concrete + with a rubber like coating. A little cushion for damage to the balls + the surface it's going to be getting dropped on.


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## neolitic (Apr 20, 2006)

Just have these guys find a mason
and hire on as hod carriers.


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## concretemasonry (Dec 1, 2006)

I also like the idea of a steel core (in a joking way - ).

Can you imagine what happens when you drop a heavy ball with a high density core covered by a few inches of resilient rubber? If could be great entertainment like watching an uncontrolled huge golf ball bouncing and rolling around. - Much bigger and heavier than a bowling ball (3 to 5 times heavier) and more unpredictable.


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## c.c.co. (Nov 13, 2006)

Great info, thanks y'all. The mold is coming from the guys that have made plenty of these and train with them a lot. So it sounds like mix dry, pack often and I was already thinking of using my 1/4 sheet sander to vibrate the mix to get rid of bubbles. Sounds like just a crack resistant premix from the depot will work.


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## Tscarborough (Feb 25, 2006)

I still find it hard to believe that you train with 184# and 360# balls. What do you do, roll them around the yard?


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## lukachuki (Feb 11, 2005)

c.c.co. said:


> Great info, thanks y'all. The mold is coming from the guys that have made plenty of these and train with them a lot.


I agree with TSC! Train what, how, and why?

I'm guessing pack mules, pack llamas or possibly packing camels!


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## c.c.co. (Nov 13, 2006)

I'm not sure where you are getting these estimated ball weights but my training partner said the first one will be 175lbs then get heavier after we perfect the construction. We are making them to lift from the floor and place on stand kind of like a deadlift or a clean and jerk type of exercise. Strongman competition style.


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## Tscarborough (Feb 25, 2006)

4/3*pi*r^3=volume of a sphere

for r=8:

2138.64

2138.64/1728 (Cubic Foot) = 1.24 X 150 (weight of CuFt of Concrete) = 186 #'s

For r=10:

4178.33/1728 = 2.42 x 150 = 363 #'s


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## lukachuki (Feb 11, 2005)

OK OK i couldn't resist... a photo montage.


Just the visual images i'm imagining as I try to figure out what is really going on....obviously I don't have many facts to go off of.



































and i apologize!


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## 4th generation (Mar 28, 2008)

Yes well I was deep in thought trying to figure out how to get those rocks, round balls and spring thingys into the back of the bus there when someone .. hey how'd you get those pics?


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## lukachuki (Feb 11, 2005)

4th generation said:


> Yes well I was deep in thought trying to figure out how to get those rocks, round balls and spring thingys into the back of the bus there when someone .. hey how'd you get those pics?


Private investigator with a huge lenz. I investigate most OPers.....some people just moderate, i do background checks.


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## c.c.co. (Nov 13, 2006)

http://www.youtube.com/watch?v=PiuRdNuVrrM&feature=related

A lot of guys that use there body for a living end up with injuries due to lack of training or not using proper form when lifting items. Obviously the heavier you go the harder it is to keep proper form. I always found that if I train heavy when I really can pay attention to being safe and using correct form made the lifting as a framer back in the day a whole lot easier. The harder you train for the task the easier it becomes. Turns a four man glue lam into a three or two man glue lam. Luckily I am not on the labor side of the buis anymore but the extra strength I have built over the years comes in handy in many tasks outside the work place not to mention being strong is nice for mma training which is an incredible cardio workout.


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## Tscarborough (Feb 25, 2006)

Ok, OK, I see that you are aware of the weight. Fibermesh, latex additive, and good 4000 PSI bagged concrete should do it.


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## lukachuki (Feb 11, 2005)

c.c.co. said:


> http://www.youtube.com/watch?v=PiuRdNuVrrM&feature=related
> 
> A lot of guys that use there body for a living end up with injuries due to lack of training or not using proper form when lifting items. Obviously the heavier you go the harder it is to keep proper form. I always found that if I train heavy when I really can pay attention to being safe and using correct form made the lifting as a framer back in the day a whole lot easier. The harder you train for the task the easier it becomes. Turns a four man glue lam into a three or two man glue lam. Luckily I am not on the labor side of the buis anymore but the extra strength I have built over the years comes in handy in many tasks outside the work place not to mention being strong is nice for mma training which is an incredible cardio workout.



Actually the picking aside....I do agree that exercise is a really good thing. Without it i'm miserable. Although when it comes to strength i feel that if i can consistently raise my hands over my head i'm plenty strong.


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## Tscarborough (Feb 25, 2006)

You should also water cure them for a week or so then densify them with sodium silicate.


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