Consumer grade ballistic concrete testing

I mentioned testing a very low water, no slump mix. I found the application for that: Concrete roads.
We all know concrete roads stand up to constant pounding for 10 years before any maintenance is needed. I don't want to build a concrete road, but maybe precasts for buildings?

 

Question is , if some one is using a 50 on your wall,, what if any thing do you have to seek and destroy the aggressor ?
And , if the pock marks made in the wall by said rounds restriking the same hole repeatedly would eventually break through yes ?Only as an example , I took my .17 HMR a100' and destroyed an unused 8"X8"X16" cement block, wall and web in 3 rounds.
On your concrete, how well does it endure the energy of say a .308 or 30/06 of say 100 yards at the same spot ?
If I were an especially hungry desperate raider group, with the means, and found upon some one this heavily fortified, it would be difficult not to be tempted to engage and even join forces to find away around it.
The fancier the safe the greater the prize.
That being said , One might consider an out side skin that is both fire resistant and plain . "corrugated sheet metal"
Bound tight enough to the wall that pieces that occur would remain on the wall still performing to some degree .
That being said, it would be difficult , with out getting close, to see what, if any thing is happening to the wall it's self.

 

30 pounds of steel per yard is nothing. Just thinking hypothetically what I might use would start at 30 pounds per yard and go up to as much as 70lb per yard.
But these ideas need to be tested because it may be a waste of money or not work at all.

No slump mix may not work at all for this application, still going to test a sample.

The only info I can find on the military mix is does not appear to unusually strong, it looks like it's made to be poured into thick forms, not crack during curing and it's relatively cheap. If you encountered some well hydrated 50 year old concrete it could be fully cured and almost by default have a compressive strength around 10,000psi.
A 7 bag mix roughly translates to a 5,000psi@28 days mix today.
Eventually I'm going to use 6,500psi mix and try to make it stronger, for testing purposes.
My guess is a 6 or 7 bag type mix will be the best for the money.

One of the points of using thinner stronger concrete is to make it easier to hide. Throw a fire proof but non threatening stucco facade over a 4 or 5 inchs of enhanced concrete and it looks like any other flimsy 2x4 building.

What if some one has a 50Cal or this gun or that gun is so far out side of the scope of this why keep bringing it up?
That's not the point at all.
Their may be no countermeasure at all for the threat because there are no raders. Some one may want enhanced concrete for a tornado or hurricane resistant building or shelter.

 

I had been reading that damp or wet cure concrete is stronger.
But was unable to quantify a how much or how long until now.
If you can keep a casting damp or wet it will cure to up to 130% of rated after 7 days, up to 150% of rated after 28 days and 200% of rated at 1 year, but that's best case scenario. And no less than 120% of rated at 3 months, no less than 130% of rated at 6 months, 140% at 12 months.
Just have to figure out how to irrigate, flood or other wise wet the pour for that long. Most building schedules barely allow for a 2 or 3 day pause for the concrete.
So it may not be practical for most builds.
Makes me think it would be ideal for precast.

 

Assuming you are still dealing with paver sized samples, sink 'em in a feed trough or local pond.

 

Yes for small scale I have a plastic container I am going to put water in and drop the samples into.

But if I can't go full scale because of cost or because its just impractical I'm not going to test it.

For example, using 100% poly strength booster to make a test sample. Sure I could make a sample but to scale it up would cost $300 per yard to wet it just using nothing but poly booster. Then you would need around 12 yards just to do the walls around a 900ish square foot house 4 inches thick.
I just don't think that large scale for 100% booster is possible. Unless money was no object and the word "budget" is not in your vocabulary.

But I don't see any reason why a full sized build couldn't be kept damp for 90 to 180 days using coverings, sprinklers, drip irrigation gear, pumps, timers and so on. Or flood it and cut the doors and windows out later.

 

The Canadians have a report on testing different calibers being shot through walls. The results were interesting. I know much of the information on the report attached is useless to your thread but it does show the results of a .50 being shot at a few of the walls.
http://www.claybrick.ca/site/clay_brick_assn__of_canada/assets/pdf/cmri_bulletproof_project.pdf

 

Yes stucco is pretty much useless.
Their results are identical to mine.
But if you have a stucco home all hope is not lost. If you could afford to throw on a layer of foam insulation and restucco it becomes far stronger and more energy efficient.
One layer of stucco can't stop a 22LR but 2 layers of stucco with a layer of foam between will stop 230gr FMJ 45ACP from a pistol and 22mag from a rifle no problem.
I plan on doing a test where I slop on another layer of stucco on top of an old layer to show how much foam helps.

 

I'm starting to think that two standard concrete walls with earth and sand cores or rock filled gabions placed around the walls might be more practical and cost effective. Perhaps different techniques where is makes the most sense? This is a pretty intriguing subject.

 

My GT36 chicom air powered vibrator came in. Big air powered vibrator.
And I found a cheap slump test cone, some one was selling a used concrete slump test cone as a "concrete construction cone".

Yes this extra hard concrete could just be the thiner hard outer shell to a building, with a foam or earthen mid layer and a cheap normal concrete inner wall poured heavy.
I believe thinner layers will be best all around. For stopping rounds, storm debrie and heat transfer.

 

My first sample.
4,000psi air entrapped, medium workability, standard 7 day damp cure, left to sit for a month in open air.
First hit with the 22mag looked a lot like the store bought paver, blew a 5/8 inch crater in the front, but no spalling on the back, but did crack the sample.


I figured after the 2nd hit it was going to be done...

Second hit was almost identical to the store bought paver, close enough for the 2 craters to touch, but it didn't blow the block to pieces.

No spalling but made another crack.
The 3rd shot did it in. It looked like it was hanging in there but it fell apart as soon as I touched it.



The back side had no spalling but some chunks fell away when the block broke apart.

Based on this adding steel or tough plastic mesh will help a lot since the blocks shouldn't break apart nearly as easy.

 

It's too early to make any definitive result but thinking about it the other day about the cost of additives.
Unless the polymer additive does something pretty freaking amazing at well under 50% concentration.
(The cost of replacing water with 50% poly booster will be around $150 per yard)
Sticking with steel mesh or plastic mesh will likely be much better value.
Adding 3 layers of plastic mesh to 1 yard of concrete in a 4 inch wall would cost less than $25.
1 layer of steel stucco mesh would. Cost about $30 per layer on a 4 inch wall.
My WAG (wild ass guess) is that $25 dollars worth of plastic mesh or $30 worth of steel will be far more effective than $30 worth of poly booster.

The 25% poly booster concrete sample is next on my hit list.
To make 1 yard of concrete with 25% poly booster would cost at least an extra $75.
Even $75 per yard will buy a lot of rebar and mesh.
Or a ludicrous amount of steel at scrap yard prices.

 

As I proved with the stucco tests an inner and outer hard shell with something soft in the middle is the way to go.
Most of my testing will just be on concrete since it appears to work pretty well most of the time in its current state.
Most of my tests are just going to focus on just concrete, which can be used as part of a multi layer system.
If I was going to do a new build what I would do for the walls is use something like the ICF block system, place some steel rebar down in the ICF forms, order a few truck loads of military 7 bag mix, toss in a few enhancements like chopped fibers and throw a heavy stucco outer shell over it or brick over the outside of the ICF and call it good.

 

The diamond core bit's auger will be here today and I can start collecting nice straight cylinders of samples for crush testing.
My samples will be about 1 inch wide, so about 0.78 to 0.75 square inches. Shouldn't be too difficult at all to crush.

 

I was looking at thin application ballistic concrete for 5/8'' to 2'' application.
They claim 2 inches will stop 30-06.
It's rated for 9,000psi compressive strength.
And it's expensive.
If you have to ask how much it costs, you can't afford it.
Unless you are in Las Vegas NV and don't have to pay Shipping.
I can afford it, but the average person likely can't afford to have 3,000lb of concrete bags shipped half way across the country.
This set of tests is based around what we in the United states can find at our local hard ware store and mail order from the internet with in reason.
Ordering enough fiber additive to do a house worth of concrete is definitely affordable. We're talking like $100 to $200 to do 9 yards of concrete.

 

I tested the 25% poly booster sample.
As far as I can tell the 25% poly booster actually did help. There was no damage what so ever on the back side of the sample after the fist shot.
The sample did develope a crack.
Also the bullet embedded into the concrete on the first shot.
But unfortunately I didn't move the sample enough and put the second shot right on top of the first and broke it. I want them to land about 2 inches apart.
Remember the regular concrete chipped on the back side after the first shot.
An improvement, but I don't know if it's worth $75 to make each and every yard with 25% poly booster.

Bottom line, does adding only 25% poly booster to standard concrete make it stronger?
Yes it appears to.
Is it cost effective?
Probably not.