Consumer grade ballistic concrete testing

I actually am planning to run a test on a hard ware store paver where I epoxy it.
Do this for 2 reasons, I don't have to wait a month for concrete to cure and we already know the mostly sand hardware store pavers are severely damaged by just one round from a 22mag rifle so any improvement will be very noticeable.

I use that exact truck bed liner on all kinds of stuff, my home made welded steel TV stand, 2 trailers and the back of my truck are all painted with it, it's pretty much just rough paint. I'm pretty sure it won'thelp much.
The rhino liner truck bed liner that makes everything you put it on more damage resistant is a 2 part epoxy and they put it on at least 1/8 of an inch thick.

Knowing if slathering up your existing concrete with epoxy to make it stronget could be good to know.
Improving an existing structure definitely has a real world application.

 

I did another control test with a hardware store paver.
I was getting trigger happy and wanted to shoot some stuff.
Now this one was at least from 2012, been sitting out side, getting rained on, frozen winter so on and so forth.
Completely different results.
I don't know if the new pavers are cheaper or not cured fully or what.
1st shot, cratered the front and cracked it, no spalling, like 4,000psi concrete. Second shot, it was still in one piece aside from the ejected material.
3rd shot busted it.
So my variable are, new ones are maybe cheaply produced and/or not cured.

This makes me want to start some long term tests. Where I cast some blocks and let them soak for at least a few months.

 

Everything is back to normal.
I bought some fresh hard ware store pavers, shot it with the 22mag, cratered the front, cracked the block, blew a 3 inch wide 1/4'' thick chunk off the back side, exactly like the first one I did.
Second shot about 3 inchs away blew it apart.
I like consistent results.
After I got spalling on the back of a paver I took another new paver and slathered the back side with fast cure epoxy resin.
Applying epoxy should be doable large scale. I found you only need about 1 fluid ounce per square foot, so a gallon of epoxy should cover at least 100 square feet. Remember 1 yard of concrete makes a 4'' thick 9'x9' wall, 81 square feet.
I applied 5 minute set, 1hr cure epoxy to a paver and gave it several hours to cure and shot it.
The results were very interesting.
I don't think epoxying the front will make it much more damage resistant, only do the outside if you want it water proof.
The thin layer of epoxy stopped the spalling from blasting away the back of the paver. Now that's a result!.

That's a dramatic change. So far this is my favorite testing artifact.
The only step up from this I can think of that would be affordable would be to go with a layer or 2 of fiber glass and epoxy on the back. Fiberglass can be had relatively cheap. If you could afford to do the entire wall 8 or 9 feet high good, if not just go 5 or 6 feet tall a little off the ground or just do around doors and windows.

Core drilling.
I got my core bit and auger going today drilled about 20 cores out of pavers and the 25% poly booster samples. My poor little drill press which only has like a 1/4hp motor, the little motor got hot to the touch so I figured I will core the 4,000psi control later.
Now just have to devise a way to crush the cores in a manor where I can measure the force, I'm thinking home made hydraulic press with hydraulic pressure gauge.
My air entrapped cores had quite a few air pockets.

 

These guys know what's up.
In a Nutshell | Hurricane and Tornado-Resistant Concrete Houses

Not valid for atomic blasts or meteor strikes?

Hold my beer.

 

I had been wondering how fumed silica improves concrete.
Was it just the composite nature of the 2 materials on a mechanical level or was it a chemical reaction?
I didn't know, but I finally found why.
The hydration reaction creates Calcium Silicate Hydrate and left ovet Calcium hydroxide, some of which will slowly become more Calcium Silicate Hydrate. You want more Calcium Silicate Hydrate, to get more the cheap and easy way is to do a damp cure for 3 to 6 months if you have 3 to 6 months.
Well turns out the fumed silica reacts with the free lime and makes more Calcium Silicate Hydrate.
The fumed silica does improve the liquid concrete properties too.
The free lime also tries to degrade any fiberglass used in the mix even if it's the proper fiber glass intended for concrete use.
Fumed silica is not outrageously expensive either. If you had a good source you could add a lot of fumed silica to concrete for $50 a yard.
I'm thinking paint and body shops might be a good place to try. Or maybe your local concrete mixer has a train load or 2.

Edit:
Fumed silica is much cheaper than I originally thought. I found 10lb shipped for under $100.
Fumed silica is so light weight it's normally measured by volume. So 10lb is a really a lot.

 

This evening I made a test sample using my small air powered vibrator block.
I made a low workability mix with out much slump. Sloped a few scoops into the form started the vibrator then scooped the rest in and continued to let it vibrate for 10 minutes. Some air pockets worked their way to the surface during this time.
I hope I didn't completely stratify the mix.
The air vibrator was screwed onto the bottom middle of the form.
The idea is someone takes normal 4,000psi mix, pours it into a form and uses some sort of vibration creating mechanism to vibrate the forms.
Cost per yard? Unknown.
Concrete vibrating is an industry standard, I'm thinking the equipment could be rented maybe?

Then I made a slightly slumpier mix and put it between 2 layers of plastic mesh mesh.
The scenario here is some one lines what will be the inner and outter walls of the forms with mesh and just pours in the mix. Used 4,000psi mix.
I found that just doing this actually absorbs the mesh into the mix pretty good. I was worried the mesh might be sticking out and look like crap or some one might just be able to walk by and rip off the mesh but this wasn't the case at all.
The cost of adding 2 layers of plastic mesh per yard on a 4 inch thick wall should be less than $15.

I still have plenty of 4,000psi combinations to test.
I still need to test 3 layers of plastic mesh, 3 layers of stucco mesh. Combination plastic and metal mesh, 3/8 rebar, Chopped fiberglass, Fumed silica, long term wetted cure.
Make a 5,000psi aka 7 sack mix control and a 6,500psi mix control.
With the 5,000 and 6,500 mix I'm not going to retest everything again. I will do a test of 2 or 3 admixes or modifications on a 4000psI sample then if it works I will do the same thing but with 5,000 and/or 6,500 psi mix.

 

Talked to the engineer down at the pre cast plant on Fri.. Three trains of thought to consider for cost. Fiberglass mat made from house insulation in the center of your cast. Increase your air percentage to 7. Strength loss/ flexibility increase. Very large aggregate over 1". Nothing under a 3 foot thick will stop the .50 cal with continuius hammering on one spot and that just is going to buy you some time. His thoughts were to combined the fiberglass though the mix with big aggregate and wire deck mesh of 1/4" dia. with 4" squares and a 2' thick wall.

 

Great thread, and the Fiberglas insulation idea is intriguing. I think if they are coming after you with 50 cal you are probably dead if you haven't already bugged out.

 

The problem with going 10 inches thick or even a foot or more on 5,000psi or higher mix you have to watch out for hydration reaction heating.
For casting over a foot thick you may not even want to use 7 sack aka 5,000psi mix.

Everything I can find about fiber glass concrete is its a favorite of the precast industry. I have not found exactly why they prefer fiberglass over synthetic organic fiber. It may be cost but the fiberglass is about the same price as polypropylene or nylon as far as I can tell, but I'm not exactly buying it by the train load.

4 inch square 1/4 inch thick is just too big for 12x12 samples. Let me price it, weigh it and see if the cost could be scaled up to building size. I do know this 4x4 inch 1/4 wire rod fence gets used in drive ways a lot.
If it looks like it could work I will look at doing some tests on smaller non-chicken wire garden mesh that has roughly 2x2 inch square holes and is made with 12 to 16 gauge steel wire.

But I'm not testing 50 bmg rounds against concrete on account of I don't have one, the test forms would be big and expensive and it's way out side the scope of my tests.

The scope is test adding individual variables such as metal or plastic mesh, poly strength booster, vacuum, vibration, fibers, fumed silica, wet cure on 12x12x1.75 inch blocks against multiple control samples.
And tanking core samples and crush testing them.
Then test surface modifications and coatings on hardware store paver blocks which are severely damaged by 1 shot from a 22mag rifle. Any improvement is easily confirmed.

Then also a little work on improving existing stucco. Because that's what my crummy paid off house is made with.

 

ive been following this thread cuz its so interesting but mostly its way over my skill set and i have a question

isn't structure shape for hurricane, tornado etc just as important as the material? (im not touching the 50 caliber thing cuz if it comes to that i'm walking out and letting them shoot me if i cant get away or one of my buddies will go ninja assassin, its all over my paygrade)

I ask the question about shape because there is a guy in Florida whose Dome home survived all of the hurricanes when everyone else was torn up.

Monolithic Dome homes, schools, churches, storages, gyms and more | Monolithic Dome Institute

back to balistic testing

 

The dome deflects the wind so it gets less force. Concrete can be shaped to deflect the energy from a bullet, but you need to make sure you aren't deflecting that energy someplace worse.

 

A dome could be made out of wood and survive a nasty hurricane.
Unfortunately it will be several days before more of my samples are ready.
I may whip up a hardware store paver with fiberglass and epoxy backing. Just need to look up costs of fiber glass then uses my 1 square foot paver to determine how much epoxy it will take to wet the paver and fiberglass.

The beauty of my testing concrete sample testing is it could be used for anything.
You can see what standard concrete will do compared to standard concrete plus something that can be affordability added to a large scale concrete job.
Want to build a survival dome, yep.
Want to build a standard building with 4 inch walls and want to add something in the forms in addition to rebar to make it stronger, this applies to that.
Making something out of concrete blocks and want to fill in the blocks with something better than standard concrete, yeah I'm testing medium workability small aggregate mixs that could flow into the block voids.
Using ICFs and are stuck with 4 or 6 inches of thickness and want stronger than standard concrete, that's in here.
Build something out of concrete that doesn't look like a fortress, yeah.
Calling a concrete truck and want to add something to the mix before they pour, yeah I'm testing several things like that.
Live off grid and can only work with what you can carry in on the back of a 4x4 pickup and calling in a concrete truck is out of the question, yeah this might give you a few ideas.

Want to improve existing concrete? That's pretty much any test involving a hardware store paver.

 

Have you all seen the emergency concrete shelters?
Inflate add water and wait .
Looks like a concrete Quonset hut .
Add some rebar and stone to the exterior and your covered. got your own mausoleum .

 

On the subject matter off backing concrete with fiberglass plus epoxy and making a form 4''x4'' square 1/4'' inch wire fence in it...
I speced and priced out fiber glass, I knew it would be fairly cheap. I figure you want a 6 to 7 ounce per yard weave.
It looks like the price on that would be around 30 to 50 cents per square foot or would cost up to $40 per yard of concrete to add it to a 4'' wall.
So one layer of fiber glass plus epoxy you are looking at up to $150 per yard if my estimations on how much epoxy the fiber glass and concrete will hold are correct.

4''x4'' inch 1/4 or 3/16 wire panel is 5'x16' foot for $50 for 80 square feet, 1 yard of concrete poured 4 inches thick is 81 square feet.
So we will say these wire panels are $50 per yard and weigh at least 40lb. So one panel per yard is all the steel your concrete will ever need and then some.
The only thing I don't like about the 5'x16' panels is I'm trying to be all scientific and shit and I don't know the exact weight, because knowing exact pounds of steel per yard is kind of important.
Putting 40 to 60 pounds of steel per yard is going to to make some pretty tough concrete.
So to test it on small scale I'm going to try and get some 2''x2'' or larger heavy duty wire panel.

 

@oil pan 4 I happen to be in this field of work so maybe I can shed some light on a few things.
ICF can be poured at almost any thickness from 4" to 3'.
Normal concrete will weigh approximately 150lbs per square foot with there being 27 cubic feet per cubic yard would be around 4000 lbs. there are a multitude of additives that can be added to concrete to strengthen and increase the flexibility.
Using www.quadlock.com you can build walls that are 4 to 12" thick and filling the void with a concrete mixture that doesn't have to be a super strength mix but something that will flow well and by adding steel reinforcement fiber in conjunction with 1 3/4" fibrillated fiber and finished off with a microfiber will help to hold the pieces together longer to allow projectile interference. You can then purchase a ballistic material to place along the lower 4' of the walls then put the interior finishes on top. It is a Kevlar based material, not cheap but works well.

You will be only as strong as your strongest window!!!

 

Looking at what I can find pictures of anything with walls much thicker than 6 inches of concrete is going to look kind of fortress like if you want it well insulated.
The ballistic panelling is very expensive. If I remember correctly it was $500 per square in 2001, last time I worked with it.

The only problem with steel fiber reenforcement is I can't find any at the moment. So I don't know how much it costs or how much it helps.

I said a few posts back if I were building new I would just use ICF, 6 inches thick, probably a normal amount of steel, 20 or 30 pounds per yard maybe a little more. And just fill the forms with relatively normal 7 sack mix with some fiber since fiber is so cheap. So I totally agree calling up the local concrete company and using normal mix is probably the best option for most people.

What would you recommend?
For concrete reenforcement I'm testing plastic mesh, steel mesh, wire panel.
For admixes I'm trying chopped zirconia bearing fiber glass, chopped nylon, polymer strength booster, sulfonic acid with poly booster packets and fumed silica.
Curing methods are 7 day damp cure for almost all samples and some samples will be long term 90 to 180 day wet cured.
Most test samples will use standard 4,000psi mix. Some samples will use standard 5,000psi 7sack mix, crack resist 5,000psi mix, and 6,500psi mix.

 

Looking forward to the next round of tests.
I think putting something like stucco mesh in the middle of the form isn't going to help as much as I would like.
I think it will help the surface from being blasted away when it's placed on outer most portion of what would be a wall. That is about it.

I picked up some 2''x3'' 16ga welded wire fence. Should be a good test to give an idea what 4x4 inch wire rod panel might do.

I want to cast a sample with the 2x3 mesh. A second sample with 2x3 mesh in the center with stucco mesh on the strike face to test this idea that stucco mech might hold the face together.
Then 3 layers of that black 1x1 plastic mesh.

The next test samples will be stucco mesh in the center, stucco mesh lining the outer edge of a wall and a control with just concrete, all 3 came from the same mixing.

 

For walls anything lighter than rebar would not be recommended.
I would consider using #5 or #6 rebar for main structural reinforcement and adding #3 rebar to fill in the gaps.
the problem with excess reinforcement is the concrete becomes more ductile and resists flexing.
As far as crack resistant concrete you will still have cracks but the freeze thaw factor can be greatly reduced by increasing the air content to between 7 and 10 percent, use a super p to increase concrete fluidity without sacrificing strength.
I have used icf with steel 2x4 exterior frame with house wrap under stucco mesh then filled with fine dry sand in between the steel frame. this was done in layers as you work up. a veneer finish is then placed on top of this, in our case it was clay brick. the exterior looked like a normal residential structure.

our simple test went from a 22 and worked up to a 300 win mag including a 73mm rifled slug. We saw the exterior had the most damage but never had a full penetration all the way thru. all of these were shot in the same spot working all the way up. The sand did the majority of the energy displacement so it minimalized the damage to the concrete.

 

This may be some useful information to add to your research

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