Consumer grade ballistic concrete testing

Ballistic Rubber Strips, Ballistic Panels & Military Rubber

 

Everything is going to sit for at least a month.
The fiber is added by the manufacture.
The only thing is for the soft inner material, you don't want something that could burn. Since a lot of heat is generated by bullet impacts or there could be a tracer in the mix. Also ground up tires can start to burn if all the steel isn't completely removed and they get damp.
I know the construction foam wont burn that easily because I have taken a propane torch to it before and it will burn as long as you hold a torch to it, remove the torch and the flames go out with in a second or 2.

 

Well, there was that time where I decided to shoot at stuff.
Penetration :: Just in case you wanted to know | Survival Monkey Forums

 

That confirms what I figured ceramic tile would do.

 

I checked on the newest samples. The vacuum concrete sitting it's form doesn't look like the other concrete samples. It looks more like grout or mortar mix because the surface is so smooth.

 

I got the chicom GT36 setries air vibrator by, far the most expensive thing so far.
I figured this has a kill and mame hazard factor a lot lower than anything I would build.
Plus the air vibrator could go right into the mix, not just on the out side of something.

 

This thread is now very interesting. Continue gents.

 

I was rechecking specs on all the stuff I can get.
Looks like the strongest I can get today is quickcrete fast setting with the green lable. It's 7,000psi@28days.
If I remember correctly it's a lot cheaper than the fiber reinforced 6500psi stuff.
BUT it's not fiber reinforced, fiber reinforced has better impact resistance, reduces spalling and cracking kind of everything you want in ballistic concrete. So you generally really want fiber reinforced.
To remedy this situation I am buying some reinforcement fiber. One pound of fiber goes a long ways the instructions say use 1 lb of fiber per yard of concrete.

The strongest I might be able to get is quickcrete D.O.T. mix, it's 9,000psi.
If I can find it.

So the manufacturer recommends one pound per yard now only if I could figure that out. Oh wait I can because it's only 4th grade math.
One yard of concrete is 46,656 cubic inches.
A pound is 454 grams.
So you want about 0.01 grams per cubic inch.
One of my paver sized samples is about 240 cubic inches.
Which comes out to 2.4 grams per paver.

 

I found a new material to test.
Went to Lowes fence section to see of I could find some sort of metal mesh material that one might add to concrete to make it more damage resistant and still be cost effective.
I found a roll of plastic all purpose 1x1 inch square fence. It's a cheaper substitute for chicken wire.
At $25 for 400 square feet it's cheap enough to use that's for sure.
One roll would cover a 4 inch thick wall pour for 5 yards of concrete if one layer was used.

My chopped 3/4 inch nylon concrete fiber additive arrived today. So I will be pouring some more test blocks.

I think I will make low slump 4,000psi sample using a 50/50 mix of water and poly booster. A low slump mix this scenario is just assuming it will be poured straight into a simple form with maybe some rebar, nothing special.
Another low slump sample where only watwr is used, chopped nylon is added, same application scenario as above.
A medium workability sample where this new plastic mesh is cast into the middle, this will be the plastic mesh version of the stucco mesh I poured about a week ago. The scenario is a form where the concrete mix needs to flow around and through the mesh suspended in the middle of the form.

The price difference, the stucco mesh is a little over 50 cents per square foot, the plastic mesh is 16 cents per square foot.

 

My fumed silica also came in.

Supposedly if you substitute about 10% of your aggregate for fumed silica it will make super strong concrete.
Or 4 to 5% synthetic fiber and 4 to 5% fumed silica.

Another test I would like to do is something I'm calling concrete cake.
Take standard 4000psi concrete wet it till it's just wet enough to stick together then pack it into the form.
Using around half the normal water, for slump that may fall apart due to lack of water, after a day or 2 apply a wet cloth, rewet as needed then take the block out of the form after 2 or 3 days then submerge it in water for how ever long I feel like.
I don't know what the application for this would be.

 

Russian tanks first employed angled armor because it made the armor thicker and caused more rounds to deflect. I wonder if this would work with concrete. 1/2 of steel is more like 3/4 of an inch when its angled at say 45 degrees. 12 inches of concrete angled would be like 16 inches ? I am pondering this.

I am a firm believer in sand bags stopping most any small arms. The idea of making concrete better is interesting for sure.

 

It makes it thicker in the line of fire , I saw this explained once on the military channel. If you have a piece of 1 inch armor by say 6 inches and turn it on end its now 6 inches. Angling the armor brings more metal in line with the bullet. Of course it doesnt physically make the armor thicker but by angling it it does make a bullet have to go through more material not to mention the deflection as well.

Draw a straight line and take a half inch plate and set it at 45 degrees to the line. then measure how much armor that bullet would have to penetrate. flat it is 1/2 angled? I get 3/4 of an inch . So my question stands. Would angling concrete do the same?

Short Range Media Penetration by 50 BMG AP Rounds | Survival Monkey Forums

Apparently 10 inches of concrete will stop a .50 bmg round. according to this post. 24 inches of dry sand. My bags are 30 inches long. It seems to me that a 12 inch poured wall would be great. If you find any additives that increase the resistance to penetration ? hats off to you

 

I'm thinking the higher psi the concrete is will allow stuff to bounce off with out blasting out chunks, when the rounds dig in we want them to remove less material. If the concrete is blasted loose we want it have enough composite to hold the loose chunks in place so even the loose material can still provide some protection.

In Afghanistan for years all the bunkers were concrete forms with around 2 feet for sand bags covering them then there are the hesco barriers. Sand works.
Now the barracks are just 1 foot or so thick concrete, to include the roof.

I will strongly consider doing a 4000psi control and a 6500psi control and pumping rounds into them off perpendicular. Say 15 to 35 degrees.

If some one is doing a new build and you can afford to make walls as thick as you want up to the maximum recommend thickness of the concrete (usually 2 to 2.5 feet thick) go for it, pour the cheap stuff like it's going out of style.

If you can only pour 4 inches or less for some reason maybe you want to add a layer to an existing build this is for you.

We will have to assume for now that most bad guys won't have weapons firing programmable sensor fused explosive tipped projectiles.

 

I like to cure check my samples after 24 and 48 hours.
I noticed the 50/50 poly booster mix after 24 hours was noticeably more scratch resistant than any sample cast using just water. The only other sample using just water that was any different than the others was the vacuum concrete. But this was an expected result because I read that vacuum concrete sets faster and is harder.
But the poly booster is around $15 to $17 per gallon. Problem is each yard of concrete needs 20 to 24 gallons of water. That's going to add up quick.
So I'm going to say spending $150+ per yard on just poly booster is out side the realm of possibility for most people. If you have money to burn, go for it. 24 and 48 hour cure checks are impressive.
Think I need to test a 3/8 poly booster to 5/8 water.
A 3/8 poly mix is $120+ per yard of poly booster. Better but not much better.
I did cast a 25% poly booster sample about 3 weeks ago, it was unimpressively a lot like normal concrete. I don't remember anything special about the 24hr cure check. I will do the 4 week cure check with the 22mag next week and see if there is any difference.

 

To get more data points I stated collecting core samples to crush.
The full size official PSI test for concrete is a 30cm tall 15cm wide cylinder.
Going to scale that down to 1.75 inches tall and around 1 inch wide.
I tried to core a paver with my diamond 1.25 inch hole saw on my drill press but the bits are not deep enough.
So I bought a 1.25'' wide 3'' deep hole saw on ebay.
Then I will need to build a specialized hydraulic press, which is alright because I always wanted to build my own hydraulic press.