[lgalla]

My math is bad,Cameron if a cu/ft of granite is 170lbs and a cu/ft of granite gravel is 100lbs can the spaces volume be calculated indicating the amount of resin required?This would get complicated with various aggregate sizes I assume.

That last picture I posted on engineered stone appears to be huge blocks glued together.Certainly low % of epoxy.BTW the engineered stone does not come out of the process like the picture,it is ground and polished with diamond grit.
Dry 10% mixes are not going to benefit from concrete vibrators vacuum or wetting agents.Have you ever heard of rammed earth?Semi damp earth is compacted with a ram or backfill tamper.10" of earth is ramed down to 5".
Backfill tampers are not cheap.Perhaps a$15 air chisel would work.
Larryard

[lgalla]

Walter we are tandem posting.In the early 50's or 60's{posts that is}I suggested tamping with a 2X4.You gotta ram that dough into the mold.
Pressing,vibrocompacting,vacuuming all at the same time?Can't see it working.My hindsight or eyesight is poor.
LARRY

[ckelloug]

Walter,

Not only have you collected materials with a low flashpoint, you're believing the regional mad scientist (me). You must be crazy! And yes, this is not nearly as easy as it sounds. From my reading, most formulations in use today for concretes come from Fuller's rule which is the worst grading formula in common use and then optimized by trial and error. Scientific approaches appear to be shunned except by the French and aren't accepted yet in things like building codes.

Looking at the pictures, I think that the mixes that you have photographed are the kind where there isn't enough epoxy to fill the spaces between the aggregate particles. They have a look of porosity to them in your pictures which I think display some excellent photography skills. What kind of camera do you have?

Larry,

That being said, it is possible to accurately compute the leftover space in a mix given the volume percentages of the aggregates or each size (or weight percent and densities). Unfortunately the calculation is extraordinarily complex and uses data of a type that it appears de Larrard is the only one who has collected (and published in his book and a french paper that has to be bought from the french government department of roads and bridges). His model uses branches of math like "calculus of variations", a branch of mathematics that deals with finding optimal functions to solve optimization problems, which I have only heard about and never seen applied to problems before. The calculations aren't really possible without computer software. I am unfortunately having some difficulties getting what the book says translated into working software due to the fact that de Larrard assumes a lot in the book and I haven't been able to work back to his assumptions yet.

Since the weather here has turned lousy for shop building, I guess I have some time to beat on de Larrard's models now.


Zumba,

I'll think about your compaction idea. It seems to me that adding the epoxy to the aggregate under vacuum ought to make the problem a lot less bad but the problem still remains that until you know the actual packing density of your mixture, you don't know how much epoxy is actually enough. Just because you only used X percentage of epoxy doesn't mean it was enough.


Grr. I'll stay tuned but I'm going to sit here and write version 3 of my de Larrard Simulator: the new and improved model with the stupidity compressed out that gets answers that don't invole 273% material densities and the like.

--Cameron

[lgalla]

Cam,Grr. I'll stay tuned but I'm going to sit here and write version 3 of my de Larrard Simulator:
That should read "V-3 of my De Ckellog simulator"

the new and improved model with the stupidity compressed out that gets answers that don't invole 273% material densities and the like.
Should read "with the stupidity vacuumed out"
de Larrard assumes a lot in the book and I haven't been able to work back to his assumptions yet.
Quote Benny Hill, "To Assume,Makes an ASS of U and ME"
[Scientific approaches appear to be shunned except by the French and aren't accepted yet in things like building codes.}
Cameron,being 1/2 French Canadian or 10% by volume,I understand the French
ways.You will not fully understand the papers unless you chain smoke Gaulloises Gitanes and sip 1947Cheval blanc at $1802 a bottle.
Larryard

[walter]

Cameron,

Could you please educate me on 3M fluorosurfactants. Is the recommended 0.05-0.3% level by volume or weight. Do you add it to epoxy before hardener? How do you actually use this thing..I only have MSDS.

I was bugging my local supplier about coupling and deairing agents. Apparently they don't cary Dow products anymore. And they seem to be getting tired of me! lol But I scored a bag of G800 Zeeospheres and a sample of Novec 3342.

The sample is like 4 kilos..

[ckelloug]

Walter,

I've got the product data sheets for Novec FC-4430 and the slightly more aggressive fc4432. They don't say whether it is by volume or weight but I'd say that volume in proportion to the epoxy is good enough. All of the data that I was able to get came from 3m's web site here and it's better than what they sent me.

http://solutions.3m.com/wps/portal/3...oatings/Novec/

The kicker is this, these surfactants and the deairing agents that you just got are so powerful that I suspect you probably don't have measuring tools accurate down to their normal usage level. I'd wager that for the size of epoxy batches that you make that the maximum reasonable Novec proportion is going to be something like 5 drops from an eyedropper and that might be generous: depending on the dropper, it could be as low as 1 drop. I've got a .1g scale and that's not really good enough for small batches with the small quantities we're talking about. As far as I know, the effective amounts of these things are determined by trial and error and while I've never used them, my advice would be to start with a tiny bit and work you way up. I'd think it's probably best to mix the epoxy first and then add the novec and the deairing agents as the novec will likely make the epoxy want to foam a touch. . .

I got my samples by clicking on sample on the respective web sites. I'd suggest you do the same with dow corning if you are interested in their coupling agents after your work with the BYK A8000. I'll let you know when the dow corning samples come in here.

I've had no trouble getting samples over the web and might suggest you try this for your future sample runs so that you can save a bit of your rapport with the local supplier for later.

The Novec 4430 and 4432 will behave like soap and may cause some unhelpful bubbling issues on their own. I haven't tried them yet as this damned aggregate simulator is driving me nutso. I've got the right curve shape but I've got an annoying error I can't locate which I suspect may have to do with the correction he does for container size which also affects the correct aggregate ratio!!! I haven't implemented it yet. . .

If you've got any specifics for discussion, PM me as I'm at the computer pounding on this aggregate simulator.

--Cameron

[walter]

Good info, thanks!

I'm hitting the workshop- need to start drilling for rails, motor mount, the whole thing. Things are getting exciting as I'm getting closer to pouring my gantry!

Still have to build the mold and test the additives(!). It may slow me down, but I hope I will finish soon.

[greybeard]

Walter - mail en route, and thanks.
Just to give you a laugh, and some idea of my working methods, I attached here the first shots of my spin casting rig.
I thought I'd best test it with water before I painted the walls with an epoxy/sand stripe. All seems OK, and tomorrow morning will be the first epoxy tests.

I've been thinking of how I'll get the mix into the test tube.
The simplest seems to be to use a central tube down the axis, pour the dry pre-mix around it, followed by the resin mix down the center, then withdraw the center tube.
Fortunately, my various bits of tube will give me a 20% epoxy for the first test, and I shall be interested to see if any excess migrates to the central axis.
How have you been cutting any samples ?
I'm assuming something like a disk grinder, possibly with a diamond cutting disk.

Regards
John

Edit - the photos are left to right 2800rpm, ~2000rpm, and 900rpm with water as a test fluid.

[ckelloug]

I've finally managed to produce an aggregate simulator that agreed with two of de larrard's simple cases. The code is awful and has to be recompiled for every run as it's still very much a work in progress. The cunning old badger fails to give you a couple of the constants you need to duplicate his work probably because he'd like to sell you his simulator.

For my first run not using canned data, I tried an analysis of of Walter's mixture from <A href="http://www.cnczone.com/forums/showpost.php?p=312253&postcount=1639">Post 1639 </A>

Using the upper value each size range walter gave in the post and assuming .03mm for zeospheres, I asked the simulator what the packing density should be.

Since it works by volume, I assumed that 25% by volume of the solid fraction was taken up by the zeospheres and that 15% each were taken up by the other quartz fractions.

The model thinks that the mixture contains about 29% voids if poured into a container with no epoxy. If vibrated, it is expected to compact to 27% voids. If vibrated under pressure, the model expects it to compact down to 20%. The book indicates that vibration under pressure is the most effective method.
It also says that the hypothetical best compaction this mixture will achieve is about 15% voids.

As a result, I think this mixture suffers from the problem described recently of using a small quantity of epoxy but not enough to fill the voids. This mixture will be too dry if if less than 20% epoxy by volume is used but 30 percent is the conservative figure to ensure no voids.

Walter hypothesized about the zeospheres making the mix dry. I ran another model calculation evening out the volume percentages of the various components to 16.6 percent of each. 29% 27% 19% and 13% were the void percentages for poured, vibrated, vibrated under pressure, and hypothetical maximum compaction. I further ran the model asking it to optimize the density by changing the amount of zeospheres. It said that when vibrated under pressure that 16% zeospheres by volume would have been optimal yielding 20% voids.

It must be stated that I haven't fully got this validated yet and I was forced to assume values for some constants based on literature values. As far as I know however, this does give a rather fair relative notion of what is and isn't going to work well although it may be off a few percent in the absolute density.

--Cameron

[walter]

Love the spin casting idea. You're officially admitted to Mad Scientists' Club!

Speaking of mad scientists.. Cameron, check this out:

1000g total (59%+25%+16%)

590g of quartz (5x118g)
250g of zeeospheres
160g of epoxy
_

[lgalla]

I don't understand vibration under pressure or vacuum.I thought these were separate processes.If you press,in theory the aggregates will lock together and vibration cannot occur or be useful.If you vibrate to success the aggregates are aligned and further pressing will only compress entrapped air as aggregates and epoxy are not compressable.
Mixing under vacuum is probably the most useful starting point with enough epoxy to fill the voids.Tamping as walter has done is probably a good method as a previous post I made on Ramed earth.
Good concrete has 7%voids.Does anyone remember the claimed density of commercial E/G?From this we will be able to calculate the void content assuming 93% aggregate.
Another pitfall I see is:if I take a block of granite 12X12X12 and brush on epoxy I may acheive 99% granite/epoxy mix or better.John said before "jigsaw puzzles in the dark"If you took little square granite pieces and glued them to gether you would have very low epoxy demand,but questionable strength????
Surfactants&wetting agents:Epoxy's are a difficult mix,.05% surfactant is very difficult indeed.The present problem is aggregate packing ratios,epoxy viscosity etc.Surfacants will not help a void.I have developed A-void and have to retire.
Larry

[ckelloug]

I don't understand vibration under pressure or vacuum.I thought these were separate processes.If you press,in theory the aggregates will lock together and vibration cannot occur or be useful.If you vibrate to success the aggregates are aligned and further pressing will only compress entrapped air as aggregates and epoxy are not compressable.

Larry,

The model I am working with does not take into account the epoxy directly. Aggregates will pack together greatly increasing their densities as they are given the energy to overcome the friction that makes them site where they are. Based on de Larrard's lab work, "de Larryard" 's theory of vibration efficacy is flawed. Vibration causes the aggregates to oscillate in place and the oscillation transforms the system from one govenerned by static friction to one that is goverend by dynamic fricition. In non-engineering english: "A moving object is easier to keep moving with friction losses that a non moving object is to get moving under the influence of friction."

In essence, vibration causes the mass of aggregate to behave more like a fluid than no vibration but it is a fluid with a high "viscosity". It will flow but pressure will encourage it to flow faster and farther. When this solid fluid flows, the particles pack together as densely as the energy input can force them. If you simply vibrate a mixture, it will flow and compact under the influence of gravity. If you vibrate the mixture under pressure, it will flow and compact more.

While it is true that a bit of compression with a weight could in theory trap a tiny bit of air at the boundary between the lid and the mold, I'm not thinking this is a huge problem although lining the mold with some RTM release paper probably would solve this.

Mixing under vacuum is probably the most useful starting point with enough epoxy to fill the voids.Tamping as walter has done is probably a good method as a previous post I made on Ramed earth.
Good concrete has 7%voids.Does anyone remember the claimed density of commercial E/G?From this we will be able to calculate the void content assuming 93% aggregate.

Tamping is probably a good method of compacting but I don't have a number for the model to predict what it does so unless a whole bunch of measurements are made, I can't tell you anything about it other than it sounds good which is why I haven't discussed it today. If it's similar to rodding of concrete or aggregate, it's not as good as it sounds however.

The model and studying that I have done explain what happens to a box of rocks when it is compacted by pouring it, vibrating it, rodding it, and vibrating it under pressure. When the epoxy enters, the system gets more complicated. I'll explain my reasoning about what happens but I'm not sure that there is a wide body of published literature about anybody really knowing what happens.

The first problem is that the amount of epoxy needed to fill all voids in the "box of rocks" is dependent on how much the box of rocks has been compacted together.

Let's do a thought experiment with a big box of marbles. If this were in the geometrically regular face centered lattice pattern, it would have a packing density of 74% (percentage of the box volume). If any less than 26% epoxy was used (also by volume), there would be either internal voids or the top layer of marbles would not be embedded in epoxy.

If marbles are randomly dumped in the box, literature values show that the density is generally between 61% and 64% (percentage of box volume) and it depends how the marbles were treated after they were dumped in the box. In short, the actual percentage of the box volume depends both on what is put in the box and how it was put there. Even though it is the same box and the same marbles, in this case between 36% and 39% epoxy will be needed to fill all of the voids. Whether it's 36% or 39% depends on how and how much much the box is perturbed during and after the addition of the marbles.

You can think of it as the marbles wanting to pack together with as high a density as possible but that requires energy. They marbles get energy from gravity and pressure and vibration but energy is used up by friction between the marbles themselves, friction between the marbles and the box and drag if the marbles are in the box with a fluid like say epoxy.

Without knowing the amount the marbles would pack together if beaten on mercilessly (theoretical value), the size(s) of the marbles, and the amount of beating they've taken, it can't be predicted from theory what the density will be.

So in short, if you randomly distribute less epoxy into the mixture than the volume of the voids, even under vacuum, you will still have voids. These will just be voids that are filled with vacuum or epoxy vapors or something and they will likely end up filled with air when the system equilibriates after coming back to atmospheric pressure. The better the system is compacted however, the less epoxy will be required to fill the voids.

According to the theory Binder Skin Theory of Gamski as put forward by Gupta, the maximum strength actually occurs at a point with slightly more epoxy that the de Larrard model predicts. Gamski postulates that a 30um layer of epoxy must surround every particle for the mixture to be maximally effective. Thus, the epoxy required will never be less than the amount in the de Larrard model but it could be more depending on the veracity of the Gamski model in light of accurate predictions of the packing density.

In short, vacuum will remove the layer of adsorbed air, water vapor and other bad things surrounding the aggregate and keep them away such that the epoxy has a chance to fill the voids. The epoxy however still requires energy to flow into the voids. The energy that the epoxy can use to flow into the voids comes either from its weight, external pressure, and in some cases its temperature. The epoxy is opposed by the surface energy of the aggregate. When the surface energy of the epoxy becomes higher than the surface energy of the aggregate as happens near the end of the cure cycle, the epoxy has insufficient energy to penetrate voids and will stop trying.

The surfactants that Walter and I have acquired drastically lower the surface energy of the epoxy making it as easy as possible for it to smoothy flow around and between aggregate particles. Unfortunately however, if the epoxy runs out of energy before it fills all of the voids, then you will be left with voids even if they are filled with vacuum! It is not true that Nature abhors a vacuum: it only true that checkbooks abhor vacuum pumps though it's not pertinent.

In summary, deairing additives and surfactants are added to the system to make sure that the epoxy has enough energy to go where it needs to go and to minimize the amount of energy required (aka trouble on our part required) to get the epoxy to go there.

Vacuum ensures that adsorbed air and other adsorbed chemicals don't cause bubble voids. Air removal additives help to ensure that bubbles that are filled with air break and rise to the surface. Surfactants make sure that it takes the epoxy as little energy as possible to flow into the spaces between aggregates. Coupling agents form either hydrogen (weak) or covalent (stronger) chemical bonds between the aggregate and the epoxy increasing the strength of the bond between the epoxy matrix and the aggregate.

The additives except for coupling agents do little to alter the fundamentals of the system: they just make it easier and more forgiving. The fundamental problem is still that to get a mixture of maximum modulus, a mixture of maximum possible density must be created. To create such a mixture requires picking the aggregate sizes and percentages in such a way that the mixture can be compacted to a maximum box fill percentage.

Another pitfall I see is:if I take a block of granite 12X12X12 and brush on epoxy I may acheive 99% granite/epoxy mix or better.John said before "jigsaw puzzles in the dark"If you took little square granite pieces and glued them to gether you would have very low epoxy demand,but questionable strength????
Surfactants&wetting agents:Epoxy's are a difficult mix,.05% surfactant is very difficult indeed.The present problem is aggregate packing ratios,epoxy viscosity etc.Surfacants will not help a void.I have developed A-void and have to retire.
Larry

I respond to your pitfall thusly:

The engineering models used to describe the phenomena in these types of composite materials require that the materials in question have bulk properties based on random distribution of the components. Your granite jigsaw puzzle and epoxy countertop paint both violate the assumptions of the models for continuous composites. These two cases can however be modeled as blocks of granite glued together and epoxy paint on a countertop respectively and their properties can be easily predicted: much easier than E/G.

You can avoid a void with a surfactant if the problem at hand is the epoxy not flowing where you need it to go. Only more epoxy will avoid the issue of the vacuum void as described above. If you use any less epoxy than required by the de Larrard model, then you have an ill performing dry mix regardless. It may still require more according to Gamski but every exact epoxy mixes are likely going to be fruitless unless you know the packing density of your mixture after it is compacted either from models or trial and error.

This does however bring up another problem. Neither the theory or the practice work correctly if the aggregate sizes aren't randomly distributed. Under these circumstances, in direct opposition to Walter's theory, I'd have to say that a great deal of care needs to be taken to thoroughly mix the aggregates beforehand. Mixtures without similar proportions for all size ranges may separate when compacted and thus the properties will not be as desired.

According to the above constraints, I'd mix the aggregates thoroughly in a separate box than the storage container of the individual aggregates. I'd treat the aggregate with the appropriate coupling agent and then allow the mixture to dry for sufficient time preferably at elevated temperature and under vacuum.

I'd then mix the epoxy and add the deairing agents and the surfactants mixing thoroughly knowing exactly how much epoxy I had. I'd then pour the mixed epoxy into a fresh cup to avoid unmixed residues. I would then weigh out the exact amount of mixed aggregates required for the proper mixture and convert to volume using the specific gravity(checking to make sure that the epoxy quantity was greater than or equal to the de Larrard voids; also remembering that the actual mix properties are governed by volume not weight).

I'd then add the mixed treated aggregate slowly to the epoxy mixture until all of it was added. Curiously in this case the right amount of aggregate will probably look as though it is way too much since the whole thing will take up more volume than it will in the final product. I'd then place this mixed batch under vaccum to get the air out. Finally, I'd place the mixture into the mold, even if there seemed to be some sand or rocks sticking out. Finally, I'd put the lid on the mold followed by a couple of heavy cinder blocks and activate a vibrator attached to the bottom and vibrate the bejesus out of it until a few minutes before the mixture gels. (This assumes using one of the equally proportioned mixes that won't segregate under vibration). I'd also put a few heat lamps on the mold to increase the crosslink count in the epoxy to help keep the stiffness up at temperature.

There you have it, as close as I can bring you to a deluxe recipe for E/G without having made any myself yet. Just a bit of electrical conduit and 16 sheets of concrete board and I'll have a laboratory and be able to get cracking! I imagine my coupling agents will be here from dow Monday or Tuesday. It's been an interesting day in E/G land.

Walter,

Good work on the new mix. Seeing the cups however, I think you have way too many zeospheres. From what I've learned lately, you only want a couple percent more by volume of them than the other stuff. If you have the list of grades you're using and the weight percentages of each and the model number on your zeospheres, I'll tell you what I predict the packing density as.

Graybeard,

That looks like a heck of a spin casting contraption. It's very different that the concept that I had but I suspect that it will work pretty well. It will make tubes with the very interesting and good property than the highest strength materials are to the outside and any excess epoxy will end up on the inside where it doesn't matter. I'd suggest starting the spin out at low RPM's to make sure everything is coated and then gradually increase the speed to blazing fast while the epoxy is still liquid. This reminds me of the Rheometer apparatus used for determining the properties of concrete that I read about!

Peace all,

I've been writing this message for way too long.

[walter]

Walter,Good work on the new mix. Seeing the cups however, I think you have way too many zeospheres. From what I've learned lately, you only want a couple percent more by volume of them than the other stuff. If you have the list of grades you're using and the weight percentages of each and the model number on your zeospheres, I'll tell you what I predict the packing density as.

It isn't new mix- it's addendum to post #1639 and your simulation in post #1690.
I wanted to show you the actual volumes-it's the mix that you simulated. Your assumption was quartz 75%/zeeospheres 25% by volume. The picture shows otherwise.

The zeeospheres are G850. They say it's 12-200micron. http://www.thecarycompany.com/adobe/..._Gray-data.pdf
_

[walter]

Neither the theory or the practice work correctly if the aggregate sizes aren't randomly distributed. Under these circumstances, in direct opposition to Walter's theory, I'd have to say that a great deal of care needs to be taken to thoroughly mix the aggregates beforehand. Mixtures without similar proportions for all size ranges may separate when compacted and thus the properties will not be as desired.

Cameron,

I oppose your opposition.

Post #1659 specifically states that aggregates should not be separated beforehand.

[greybeard]

Cameron - source of confusion (for me at least).
When the volume of a fraction is given as 10% of the total volume of the container, this can then be converted to a more convenient weight using the density of the material.
BUT, do we use the bulk density, or the sg of the material itself ?

We can "get a quart into a pint pot" if we use the wrong figures.

John

[ckelloug]

Walter,

A picture is worth a thousand words, unless you send it to me In that case, a "Duh what's in that" is the response. That was a great picture however, I wanted to buy one immediately even though I didn't know what it was Have you considered a career in commercial photography?

I'll go back though the assumptions since I bollixed the assumptions on my sim run. I also need to update the simulator so that I can try things without fear of accidentally modifying it in such a way as to break the simulator software.

As for premixing aggregate, de Larrard and company where very careful to mix all of their aggregates thoroughly before packing them. I'd almost bet however that it makes the mixture harder to deair. Without vacuum, I suspect that premixing could make things worse on air voids which is what I think you were getting at in post 1659.

Mixing first does however keep the aggregate mix homogeneous as I doubt that it can be stirred enough once the epoxy enters the equation and a homogenous mix is necessary to have the darned thing pack to maximum density. Ideally, it seems like it would be best to add the aggregate under vaccum which may or not be practical for us.

My current belief is that if a non-segregating aggregate mix is used, the aggregate can be added to the epoxy without the need to stir significantly with the mixed epoxy and as long as the whole thing is heavily compacted and there isn't a huge overabundance of epoxy, under vibration and pressure it will end up with the aggregate uniformly distributed in the epoxy.

For what it's worth, the above on aggregate premixing is just theory. As Shakespeare's villain Iago once said, "Forsooth, a Theoretician. . ."

--Cameron

[greybeard]

Just to show my impatience, I'm posting these as my first lessons in spin casting, even while waiting for the post-cure to be set up. That might be several days wait, or I'll lash up some sort of heater.

A mouse-over will give you the caption to what each photo is.
The mix poured out at the end shows up the rather well all the lessons to be learned.

As soon as the post cure is finished I'll put up the first cast - if I can get it out of the tube. (chair)

1st lesson, make a good allowance when calculating volumes of resin for the amount left behind in the mixing pot and any other losses.
2nd lesson, with such a small resin volume(25mls in this first attempt)the exotherm is non~existent, so with no temperature rise the cure time is considerably extended.
Good for getting the resin through the mix, but not for anything else.
3rd, the set up is fine for unbalanced weights, but the end caps need a better fit, and a safety shroud is a good idea to avoid striping the walls and ceiling.

The next trial will be of an excess resin and aggregate mix, with no particular de-airing done.
I stir carefully, and will introduce the mixed aggregate in the way that I mix plaster of paris, by pouring the powder into a small central pile and allowing the fluid to soak up into the solid.
This will be pushed/poured into the tube, possibly with a dowel used to make a central cavity, then spun.

[walter]

John,

Nice job on the spin casting, keep them coming!

As for premixing aggregate, de Larrard and company where very careful to mix all of their aggregates thoroughly before packing them.

Cameron,

That's basically where I started- I didn't know any better. My very first mix (picture 1) had only three components, and they were mixed visually, not formulaically (post#853). I'm sure the density was better back then. I should just throw away the scale and go back to my roots

You also mentioned air voids.. I'd say they're the same- segregated or not. Here are the samples from posts #1635 (premixed) and #1639 (segregated). The latter has some carbon black in it- a bit harder to see details, but the air voids are identical.

These samples feel great and sound great, pretty close to AkvaCNC's commercial sample (except for the bubbles of course). I'm very happy with them- now wait till I get the coupling agent working! And some de airing..

Good times.

[ckelloug]

Walter,

There are a bazillion variables in all this and just because I think I can predict a few pertaining to aggregate doesn't mean that your experimental work has less value or that it will not end up more correct than my models. I have a theory right now, you have data. Theories sometimes help to produce better data and sometimes are wrong. Welcome to the domain of mad science where unlike highschool, the answer isn't known in advance.

I measured the height of the items in your cups in pixels using the ruler in my drawing program. The model predicts the amount of voids in the the mixture after it is compacted so the amount of epoxy doesn't effect the model.

I measured approximately 75 pixels for each of your components and 140 pixels for your zeospheres. For a total of 515 pixels. I then computed the fraction of 515parts for each of the components ignoring the epoxy.

This gives 14.5% by bulk volume for each of the quartz fractions and 27.18% for the zeeospheres not counting the epoxy which is the way the model works. I turned up the resolution and found according to the model that the zeosphere percentage you are adding will have little effect on the mixture density between 14% and about 30%. You're at about 27% zeeospheres and going down to 19% or 20% will likely only give a .1% increase in bulk density of the packed mixture.

The model suggests that when compacted with vibration under pressure that the bulk density of this mixture is about 80%. This means that if you have 1 litre of this mixture in a 10cm square cube maximally compacted without epoxy that at least 200 ml of epoxy will be needed to fill the voids. If the sand mixture is just poured into the container until it is full then you need about 30% of the compacted volume in epoxy or 300ml.

What I think will happen (but don't have solid data for) is that if the aggregate is thoroughly mixed and poured into a measuring container that the volume measured will be about 10% more than when it is compacted by vibration and pressure. If these assumptions are correct, 1 liter of uncompressed aggregate will make .9 liters of compressed aggregate which at 20% epoxy is will require 180 ml of epoxy.

Putting this another way, I believe it means that 1.11 litres of thoroughly mixed aggregate plus 200 ml of epoxy when maximally compacted ought to yield 1 litre of E/G with no voids assuming it is deaired properly. This leads to the belief that 18% of the uncompacted volume of the aggregate is the required epoxy volume of this mixture.

I believe this mixture has the wrong components to get maximum density based on the model results.

I'll start a new post for clarity about what I've been able to find with the model.

--Cameron

[walter]

These numbers are easy to understand, I'm getting excited about your simulator. Great work!
_