Concrete Rock Pot/Slab?
- Thread starter moke
- Start date
BunjaeKorea
Omono
It's awesome. How do you get the natural volcanic look?
@moke Bravo! good job on the detail work!
I experimented all spring and summer with different cement recipes and moldings, will have plenty to do this winter to get ready for spring replanting,
I do enjoy creating my own containers, furthermore the more natural looking designs are what I gravitate towards.
Good stuff , love to see more and keep it up!!
I experimented all spring and summer with different cement recipes and moldings, will have plenty to do this winter to get ready for spring replanting,
I do enjoy creating my own containers, furthermore the more natural looking designs are what I gravitate towards.
Good stuff , love to see more and keep it up!!
Thanks, I also plan on working on several through this winter. You’ll have to share your work. I plan on keeping this wrapped and moist for about a month then I’m going to place it outside in the elements before planting in the spring.
sorce
Nonsense Rascal
There's some slate stepping like that along my DesPlaines riverbank.
Nice.
S
Nice.
S
Silentrunning
Chumono
Moke, would it be possible to show a few progression pictures or even start a how to thread?
Most definitely, The next one I work on I will take step by step pics.
Sweet, that’s the look I was shooting for, I also made some matching small stones with the leftover cement to place in the planting.
queenofsheba52
Chumono
Wow, that slab is a real beauty!
WNC Bonsai
Masterpiece
I’d be unterested in your concrete mix. Is it a packaged mortar mix or something you made up yourself? Did you use pigments for the color? Very nice work!
Silentrunning
Chumono
That would be great. I tried to make some cement pots and they had all the aesthetic appeal of a broken cinder block. ?
Thanks,
Here’s what I’ve been using, it has a nice texture for sculpting. I picked it up at Lowe’s.
QUIKRETE® Vinyl Concrete Patcher (No. 1133) is a multi-purpose concrete repair material with strong adhesive properties. Trowels to a feather edge of 1/16" (1.6 mm). Made of a special blend of exterior grade vinyl resin, fine sand, and portland cement. Just add water.
Available in gray and white
https://www.quikrete.com/pdfs/data_sheet-vinyl concrete patcher 1133.pdf
For the pigment I went to a local concrete supply company. They had many colors to chose from. It’s a powder and a little goes a long ways, Here’s the link to the manufacturer of the pigment.
http://www.solomoncolors.com/ColorCard.aspx?ColorCardID=24
Potawatomi13
Imperial Masterpiece
Very reminiscent of Eric Krizovensky pots. He has a process that helps or prevents cracking from cold heat cycles. Quite patient you must be to make such creative pot
. Good job.
. Good job.Very reminiscent of Eric Krizovensky pots. He has a process that helps or prevents cracking from cold heat cycles. Quite patient you must be to make such creative pot
His work is amazing, thank you for the compliment. I am fairly confident this concrete will hold up to the extreme elements Utah will dish out, definitely an excellent testing environment -20F winter to 111F in the summer. I used an expanded metal armature as well as reinforcing fiber.
Rusty Davis
Shohin
Going to have to play with some of that this winter
I do same thing and have used some of that same cement on some and they laugh at my new England winters. Big thing is not to use too much water at first, when mixing. once your done and its curing is when you want to water, mist it often, the slower the curing/drying process, the stronger it will be. Wrap in tarp or plastic bag for week or more and in dark/shade, you would be good to go. I have also begun to add a little lime in the mix, which helps with the freeze thaw and wont crack. And no the lime wont leach into the plant, for the tiny amount that might, wouldn't, plus with how we water our trees it will be flushed out, if it did leach a little. But I have planted a tree a month after making a pot and it is fine. After 28 days it is 98% cured and the last like 2% will take 100's of years, all cement is like that. learned that in my experimenting/education. HAHA
Side note, if any of you heard of Hypertufa, its all the rage with houseplant people, haha. but you mix peat moss with the cement, which makes it lighter and stuff.
I have mixed everything with P. cement to see the affects. But as @moke said, the pre-mixed bags shown, are good for hobbyist and small projects.
keep on creating!
Generic User
Sapling
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Beautiful
discusmike
Omono
Amazing work!!??????
Leo in N E Illinois
The Professor
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@moke - I missed the original post earlier. Nice work. The product you chose, Vinyl Concrete Patch, is exactly the type of product I would suggest for pots and slabs, as these are ''thin'' applications for concrete. Good choice. It is a Portland cement mix, with a vinyl component that adds flexibility to the set product. The addition of fibers really reduces fine cracking, and using an expanded metal mesh will add structural strength. Well done.
I believe Eric K uses Ciment Fondue, a product more readily available in EU, not really used much in North America, except for certain specific applications. The Vinyl Concrete Patch product is based on Portland Cement chemistry, which I understand to some degree. Ciment Fondue is not Portland Cement, it is a cement with a much higher aluminum content, and much lower silica content than what is found in Portland Cement. The chemistry is somewhat different, and it reacts differently to additives than portland cement. It is also more expensive than portland cement. It does make a good finished product, as Eric K has proved. Ciment Fondue is used in foundry applications, because it is stable to much higher temperatures than Portland Cement.
@BE.REAL - mixing peat moss or any water absorbent material, like paper into a concrete mix will guarantee freeze thaw damage. With the ''hypertufa'' the spalling off of the outer surface over time, the cracking and crumbling is all part of the ''charm''. Actually a design benefit. But if you want long lasting pot or slab, do not mix any organic material into the mix. In frost free Florida, hypertufa can last 100 years. In Illinois, it might last 5 winters. But it will ''look cool'' as it degrades.
Separately I also question your addition of unslaked lime or lye to the mix. I am retired from the concrete admixtures manufacturing, and I never heard of unslaked lime, calcium hydroxide or sodium hydroxide, adding any freeze thaw resistance to a concrete mix. The concrete mix already contains a significant amount of calcium oxide, which becomes the unslaked lime or lye when added to water, adding more will do nothing more than weaken the final strengths of the concrete more towards the properties of mortar. Mortars are based on the dominant binding agent being calcium oxide reacting with water to make calcium hydroxide which reacts with carbon dioxide to make calcium carbonates (limestone). The superior strength of Portland cement depends on calcium aluminosilicates hydrating to form a much stronger matrix than calcium carbonates could form. There is calcium oxide in portland cement, but the percentage is low compared to the anhydrous aluminosilicates. Adding extra calcium hydroxide merely weakens the mix more toward the properties of mortar. Not good for frost-freeze resistance.
It is possible that @BE.REAL - you might be thinking of the addition of calcium chloride to concrete mixes. Here the effect of the calcium chloride is that it accelerates the initial set up of the concrete, allowing normal set times when the concrete is poured in cold weather. So you would see calcium chloride added in cold weather, but it actually acts on speeding up the initial strengths, and actually slightly lowers the end final strengths. Set time is temperature dependent, and for most jobs, if it is below 50 F outside it is normal to add an accelerator to the concrete mix. This is probably what you were thinking of. If you use metal, especially aluminum or iron mesh or rebar in your concrete - added chlorides, like calcium chloride will have a chemical reaction that will eventually corrode the metal and cause the concrete to fail. That is why calcium chloride is not allowed to be used in bridges, tall buildings or nuclear power plants. It is okay for house foundations, the least demanding task for concrete to perform. I hope you don't feel I'm ''busting your chops'' that is not my intent. I just don't want others to accidentally screw up their own projects by following what was probably an accidental mis-statement you made. And since I worked in the business, I thought I'd set the record straight.
There are techniques and additives that would help with freeze thaw resistance.
# 1. - One is to use as little water as possible to your mix. You want to add just barely enough to make a smooth, but still stiff paste. The amount of water needed for the various hydration reactions is so little that if you only added what the chemistry required, the mix would still seem ''dry to almost dusty''. The extra water makes it easier to work with, but the water as it evaporates leaves micro-channels, that allow water to re-enter the concrete, and when the concrete freezes, the water expands and cracking begins.
#2. - use a Portland cement mix with an additional polymer in the matrix, such as vinyl, there are also acrylic - cement mixes. These are high tech mixes, designed for patching, and have complex chemistries that should not be ''messed around with'' in the mixing process. Just follow the directions.
#3. - adding a plastic fiber, who's shape was cut to maximize strengthening the concrete (like little bow ties). This is what Moke did. Good move. Sometimes after the concrete is set you can feel the fibers sticking out from the cement paste. Just hit the finished piece with sand paper to sand the surface smooth. They will smooth right out.
For small batches of concrete, the above is all I would do. Until you get a batch size closer to one ton or more of concrete any chemicals you could add would have to be added in very small amounts. Not easy to get right without laboratory scales or volumetric equipment. Some are also not exactly safe to handle in a home setting. For large scale construction, to make extremely freeze thaw resistant concrete the redi-mix plants will add various soap like compounds to entrain air voids for the ice to back up into, naphthalene condensates and or lignin liquors to reduce total amount of water added, silica fume to create a more dense concrete, and a host of other chemicals.
I believe Eric K uses Ciment Fondue, a product more readily available in EU, not really used much in North America, except for certain specific applications. The Vinyl Concrete Patch product is based on Portland Cement chemistry, which I understand to some degree. Ciment Fondue is not Portland Cement, it is a cement with a much higher aluminum content, and much lower silica content than what is found in Portland Cement. The chemistry is somewhat different, and it reacts differently to additives than portland cement. It is also more expensive than portland cement. It does make a good finished product, as Eric K has proved. Ciment Fondue is used in foundry applications, because it is stable to much higher temperatures than Portland Cement.
@BE.REAL - mixing peat moss or any water absorbent material, like paper into a concrete mix will guarantee freeze thaw damage. With the ''hypertufa'' the spalling off of the outer surface over time, the cracking and crumbling is all part of the ''charm''. Actually a design benefit. But if you want long lasting pot or slab, do not mix any organic material into the mix. In frost free Florida, hypertufa can last 100 years. In Illinois, it might last 5 winters. But it will ''look cool'' as it degrades.
Separately I also question your addition of unslaked lime or lye to the mix. I am retired from the concrete admixtures manufacturing, and I never heard of unslaked lime, calcium hydroxide or sodium hydroxide, adding any freeze thaw resistance to a concrete mix. The concrete mix already contains a significant amount of calcium oxide, which becomes the unslaked lime or lye when added to water, adding more will do nothing more than weaken the final strengths of the concrete more towards the properties of mortar. Mortars are based on the dominant binding agent being calcium oxide reacting with water to make calcium hydroxide which reacts with carbon dioxide to make calcium carbonates (limestone). The superior strength of Portland cement depends on calcium aluminosilicates hydrating to form a much stronger matrix than calcium carbonates could form. There is calcium oxide in portland cement, but the percentage is low compared to the anhydrous aluminosilicates. Adding extra calcium hydroxide merely weakens the mix more toward the properties of mortar. Not good for frost-freeze resistance.
It is possible that @BE.REAL - you might be thinking of the addition of calcium chloride to concrete mixes. Here the effect of the calcium chloride is that it accelerates the initial set up of the concrete, allowing normal set times when the concrete is poured in cold weather. So you would see calcium chloride added in cold weather, but it actually acts on speeding up the initial strengths, and actually slightly lowers the end final strengths. Set time is temperature dependent, and for most jobs, if it is below 50 F outside it is normal to add an accelerator to the concrete mix. This is probably what you were thinking of. If you use metal, especially aluminum or iron mesh or rebar in your concrete - added chlorides, like calcium chloride will have a chemical reaction that will eventually corrode the metal and cause the concrete to fail. That is why calcium chloride is not allowed to be used in bridges, tall buildings or nuclear power plants. It is okay for house foundations, the least demanding task for concrete to perform. I hope you don't feel I'm ''busting your chops'' that is not my intent. I just don't want others to accidentally screw up their own projects by following what was probably an accidental mis-statement you made. And since I worked in the business, I thought I'd set the record straight.
There are techniques and additives that would help with freeze thaw resistance.
# 1. - One is to use as little water as possible to your mix. You want to add just barely enough to make a smooth, but still stiff paste. The amount of water needed for the various hydration reactions is so little that if you only added what the chemistry required, the mix would still seem ''dry to almost dusty''. The extra water makes it easier to work with, but the water as it evaporates leaves micro-channels, that allow water to re-enter the concrete, and when the concrete freezes, the water expands and cracking begins.
#2. - use a Portland cement mix with an additional polymer in the matrix, such as vinyl, there are also acrylic - cement mixes. These are high tech mixes, designed for patching, and have complex chemistries that should not be ''messed around with'' in the mixing process. Just follow the directions.
#3. - adding a plastic fiber, who's shape was cut to maximize strengthening the concrete (like little bow ties). This is what Moke did. Good move. Sometimes after the concrete is set you can feel the fibers sticking out from the cement paste. Just hit the finished piece with sand paper to sand the surface smooth. They will smooth right out.
For small batches of concrete, the above is all I would do. Until you get a batch size closer to one ton or more of concrete any chemicals you could add would have to be added in very small amounts. Not easy to get right without laboratory scales or volumetric equipment. Some are also not exactly safe to handle in a home setting. For large scale construction, to make extremely freeze thaw resistant concrete the redi-mix plants will add various soap like compounds to entrain air voids for the ice to back up into, naphthalene condensates and or lignin liquors to reduce total amount of water added, silica fume to create a more dense concrete, and a host of other chemicals.
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