Consumer grade ballistic concrete testing

Stucco sucks so bad I don't know if it can be helped at all.
This is what the all powerful 22LR out of a rifle does to one of the thicker pieces of stucco.
Almost everything centerfire fired from a pistol can surpass its KE. You would have to really look far and wide to find something weaker.

 

I'd suggest testing against military calibers you might expect to be in use during SHTF: 5.56, 308, 7.62x39 as well as .22LR

 

So I got to thinking.
One layer of stucco it sucko.
So what I can I do to improve it. Already talked about restuccoing the house. I don't think slathering on another half inch or so will help much. Plus I would be missing an opportunity to make the house more energy efficient.
Ok so what if I put up some of that blue medium density Styrofoam insulation and slathered on a new stucco job on top of it.
Exactly like this:

Then I figured heck I can test that today. So I did.
Note the only difference here is the old work is on black asphalt fiber insulation crap for all most all of the house.
First test 22LR.

*pop* I shot it off center because 22LR doesn't cause wide spread damage on the stucco I wanted to jam in 2 shots in on this sample since I only have so much original stucco.

The 22LR lightly damaged the foam after blowing a hole through the stucco.
The next shot 22mag.

As expected blew a hole straight through the stucco.

The second shot wasn't helped by the first.

So the foam absorbed the brunt of the bullet fragments.
no damage to the second layer of stucco from 22mag. That's encouraging.
But the stucco fragmented the light weight higher velocity 22mag projectile.
Then figured what about something big, slow moving with a lot more kinetic energy that wont fragment.
I figured 45ACP 230gr FMJ would be a pretty good test.

As you can see the 45ACP is pretty devastating but you can clearly see the bullet sitting on top of the foam and busted stucco mix.

Not exactly a so called pristine bullet.

the original stucco was only being held together by the chicken wire, but there was no spalling, it was just busted like it had been smashed with a sledge hammer. A larger sample would have done a little better.
I figured the 45 would punch right through.
Based on this, it would stop buck shot pellets pretty well but I don't think it would stop high velocity, high power center fire rifle at all.
Over all an unexpected result. Composites baby.
So hard surface, foam more hard stuff seems like the way to go.

 

I dropped my first samples out of the forms. The actual concrete pavers are harder and heavier than the mostly sand and air store bought pavers. The sample mixed with 25% poly booster was trying to stick to the form. That could be bad.

I made another paver form and cast 3 more samples this time.
Using the cheap concrete.
I cast some samples with steel mesh reinforcement. I used the steel mesh backing normally used for stucco.
I mixed up the concrete, all the concrete for all 3 samples for consistency. Made a control just concrete and no metal. A sample with one layer of steel mesh in the center as if the mesh were suspended in the form and concrete poured around it in a wall. The 3rd was set up as if the mesh lined the form and will be right at the surface.
The concrete was fairly slumpy, nice and workable but not runny.
I'm assuming that workable concrete would be desirable to flow in and around your steel and in and around the inside of the form.
I'm looking forward to some concrete trigger time.

I wanted to make a 4th form but ran out of scrap 2x4, didnt finish it and don't want to cut up fresh ones. The 4th form would have multiple layers or steel mesh, at least 3 layers.

1 square foot of this stucco mesh weighs 3.1 ounces.
So per yard of concrete say casting a 4 inch thick wall I would get a 108x108 section of wall or 81 square feet. So for each layer of stucco mesh you put in a wall you're get almost 16 pounds of steel.
So if you layer both sides of the wall with stucco mesh that's 32lb per yard, if you do inner outer and center with mesh that's 48lb of steel per yard.

 

The concrete forms are pretty simple.
Scrap 2x4 and plywood wrapped with plastic wrap to hold the water in.

 

My little pneumatic air vibrator came in its just too small, the oscillations produced just doesn't have enough magnatude to shake the air out of the concrete IMO.
I could bolt it to one of my test forms but to shake a larger amount and I'm only talking like 0.5 to 1 cubic foot I will need a much larger one.
I have the little "GT10" serries. It's too small unless you only want to vibrate individual samples.
I am ordering the much larger "GT30" serries vibrator. I think this is the largest air vibrator my gasoline powered air compressor or electeic air compressor can run by them selves at near full power. I want to be able to vibrate a full sample batch (enough to make 3 or 4 samples) for consistency.

 

I'm going to try and attach it to the sample casting form.
For large scale I would probably use a standard concert vibrator tool. Or take one of my spare electric motors and attach an intensionally unbalanced pulley to it then attach that to what needs to be shaken.

 

I converted my old pressure cooker to a vacuum chamber.
I put my 2 stage vacuum pump and automotive compound gauge.
The gauge was showing 26 inches of mercury. At 4,400 feet above sea level about 25.5 inches is a perfect vacuum.
So that's about as perfect a vacuum as you could hope for, give or take atmospheric pressure, temperature differences on any given day and gauge inaccuracy .
Let's see what high vacuum concrete is like.

Lets recap why we want vacuum concrete.
Typical concrete is 4% to 10% air, every 1% of air can reduce compressive strength by 5%. So at least 20% stronger concrete with out having to add anything, best deal ever.
My hypothesis or WAG (wild ass guess in engineering talk) is that in addition to vacuum obviously removing air the concrete is hydrophobic and there may be micro pockets of dry concrete, apply high vacuum those pockets pop and air bubbles around the sand and gravel also pop so the Portland cement adheres to the aggregate better.
I will mix up a vacuum sample and a control and see what the difference is.

Edit:
Made the samples. Medium workability. A control that was mixed and dropped in the form, the vacuum concrete was dropped in my vacuum chamber held on high vacuum for 7 minutes then dropped in the form.

 

How many days are you letting things cure before testing?

Great thread, like the up-dates

 

Everything is going to cure for at least a month.

I wanted to destroy some more stuff so I shot up a paver with 22LR.

2 rounds hit on top of each other twice so 6 total. I'm going to say pavers are fairly bullet proof when it comes to 22LR. If the rounds were more spread out it could have taken 10 to 20 to break the paver. Each bullet blew a 3/8 inch deep crater into the paver, no spalling on the back side.
So I'm thinking 22LR bullets will do almost no damage to good concrete.

 

Have fun, I dont trust anything but sand bags. Sand is soft and slows a bullet down . Im not sure what that is called but it works. Still I dont trust my bags to be sideways so we stack them with the ties facing in. It takes a pretty big round to penetrate 30 inches of sand.

The main fact I am aware of regarding ballistic penetration is that about anything will go through vinyl siding, glass bat insulation and drywall. I could shoot a .22 40 grain solid through any part of my house except the basement block wall. a 5.56 would blow holes through the block wall as would any larger caliber. My house is not a safe place to be if being shot at. It is the last place I would try and defend. Solid concrete is better than hollow blocks. Let us know how thick it needs to be to stop a .308 fmj. Most of these tests have been done and are available on the net.

 

The high strength 5,500lb and commercial grade 6,500psi concrete already have fiber glass in them. I thought I mentioned that some where on here? Maybe not.
The cheap standard 4,000psi mix does not have fiber glass.
So far I have only poured 4,000psi mix.

I'm using Portland cement with sand, gravel, then some samples will have fiber glass, steel and polymer strength booster. That is about as composite as you can get.

With what the stucco tests showed I don't think casting a single one piece wall is the way to go at all. I think something like stucco over 2 inches of medium density building Styrofoam would be the way to go and the rest of the time when there are not any tornado debris hitting your house and no one shooting at you it would be energy saving.
Oddly enough, the newer buildings on bagram air base Afghanistan were constructed this way, a thin stucco fasad over 2 to 4 inches of foam covering a concrete wall up to 1 foot thick.

I think a thin hard outer covering like stucco or even brick over something flexible and energy absorbing such as construction foam in the middle and a thick concrete inward wall is ultimately the way to go. But that's not what I'm testing.
This isn't a test of how thick to stop what.
This is a test of changing one or more variables to try and quantify the difference compared to a control. Changing 1 or 2 things could make a huge difference.

 

THAT would be interesting. By chipped rubber do you mean what you find on a military small arms range?

 

The foam would be the pricey part. I would think a person would want the two part stuff that is used in lining boxes before shipment. Build some forms, shoot the foam, add the rubber and seal the top of the form and let it set. Doesn't take long for that stuff to set up at all.

Small scale testing could be done using the expandable foam in a can and rubber I suppose.