@@faraday9234 If it's a typical 4 foot wide sidewalk - expansion from the sun will make the deficient mix apparent too.... You gotta mix for a reason...
Swiss hammers are designed to give very rough data to determine if any more testing is needed. Concrete core test will be the most accurate. And show how consistent the mix is. More than likely your dry slab will be stronger than what the Swiss hammer results are. BUT looking at concrete strength alone will not determine concrete quality. Yes absolutely your dry slab strength will hold anything you put on it. But it will probably not hold up to any freezing and thawing cycles that it is exposed to. Unless you are in a warm dry climate and don’t have any cold weather I would always go with a wet batched concrete to allow air entrainment to develop during mixing. To help protect against against freezing and thawing. I love the effort!! Keep it up! Concrete rabbit holes are always interesting to go down.
Of late there is talk of the "discovery" of self healing concrete used by the Romans. And I wonder, how well does this concrete stand up to freeze thaw cycles as we here in Ohio gets more freeze thaw cycles in a month as Italy gets in a century.
@BS-ys8zn it was the added cook lime chucks added when pouring the water mix concrete. As the concrete cracks, it open the lime chuck to get hit by water/moisture in the air which would seal up the crack
@@BS-ys8znItaly is extremely mountainous so plenty of areas get very deep snow in winter and plenty of freeze thaw cycles, however I don't know whether there is roman concrete on those areas. However it's not that relevant because modern self healing will be tested a lot before it's approved for cold areas (hopefully).
I'd like to see compression and tensile strength comparisons of the concrete samples, as well as taking a cube of each and putting it through accelerated freeze/thaw cycles in the presence of moisture.
Yep totally agree from my own experience throughout my construction career I have had to fix many mistakes of other builders and some my own and have noticed jackhammering into dry pour is always giving less resistance than a wet pour
The issue isn't the surface hardness it's the consistency through the slab. You will have places that don't go through the full chemical process and it will create weak points. Don't waste your money just mix it
I agree with @93rgratz. When it is mixed homogeneous, it will be more consistent throughout the entire slab. Home owners can certainly get away with this because they're only held to their own standard. The question has always been whether it was as strong. Now consider how well a dry pour will bond to rebar compared to a homogeneous mix???
Concrete is porous. It will wick ground moisture and fully cure over time. This is why you can dry set fence posts without adding any water. There's enough moisture in the dirt for the mortar to absorb and set. If you keep watering a slab it will 100% set and cure.
yeah you can mix it anywhere. like a bucket or wheelbarrow. that's how the discus posts here in my city where concreted in. that's how all the posts on the hicking track are concreted in. we just mix it on spot in what ever container we can.
@@riccochet704 no that's not how it works att all... the reason some idiots dry pour fence posts is because they don't have to be that strong and nobody cares if they crack as they are not that important. but it's still extremely weak and inferiour to mixed concrete. you have to mix it for it to cure and set properly otherwise it will have weaknesses in it and will crack prematurely.
I don't believe this test really shows the overall strength of a slab. It may test a point for its PSI but it can't tell what deflection that slab will take before breaking apart. And that could even be under it's own weight. Things can be hard but not necessarily strong.
I don’t have an elephant crossing at my house😂😂😂…. I just need to repair a section of my walkway that has become a trip hazard until I can get the entire walkway done and a dry pour just seems like a quick temporary fix….
I have been checking your shorts for a while now in anticipation of this test. I feel better about trying this on my backyard patio this week. Thank you sir.
Quick update, I did the pour and it was fine, except the edges were kind of terrible. I did a second dry pour with the top being mortar and it looks much better then the 80lb bag.
Exactly!! IF you can introduce water balanced enough to catalyse the mix evenly, it would be relatively strong. But it's much more difficult for individuals to keep consistency while watering a dry pour form. Without strict control, this intruduces a greater chance of variation across the slab consistency. A person might have a dry center and firm exterior or a stronger slab with a powdery exterior with a solid center. Poorly mixing concrete batches in a wet pour can do the same thing. This is why in critical pours, samples will be taken in specific durations across the truck loads. Too wet/dry, too much/little entrapped / entrained air, post-pour hydration (wet cure) as well as ambient temperature being too hot/cold. I encourage people to experiment and see their results and work with what they have. It's concrete, so it can always be knocked back out. Also, a dry pour is handy for post fixing. You tested the external hardness, which could work well for domestic patios, but what I would love to see is the standard crush cylinders molds made and dropped off to crush. To get both consistency across 3 samples each, then compared results. 3 wet-pour cylinders and 3 dry pour cylinders created, not moved for 5 days- kept out of the elements. Then one of each crushed at 2wk, then 1month, then 3 months. - ACI Certified concrete tester
Why keep out of the elements? All that concrete will likely be used in outdoor environs, so exposure to elements is guaranteed. Test it how it would be.
@@philhatfield2282 Because that is the fundamental approach to what we mean when we say "Science." It means a certain way of doing things so we can gather useful information from our experiments. In this case, there are all sorts of known effects from "Exposure to the elements." For example, if you pour concrete when it's really hot and windy, or if it gets really hot and windy during the curing period and you don't take special precautions, you end up with what's called "Drying shrinkage." If you pour concrete when it's raining or if it starts raining before the initial cure is set, you end up with a watery layer on top that flakes off, called "Scaling." I could name many more and I'm not even a concrete expert. The point is, what we want to test is NOT the effect of the weather during curing. What we are talking about testing is the construction method. So the proper way to do that is to eliminate as many of the other problems that you can between various tests. If they are all cured in a room at regular room temperature and with a normal moisture level in the air, you eliminate many of the other sources of strength variation and the ONE really important variation is the ONE thing you are trying to test. Also, "Keeping it out of the elements" is exactly what you do in real construction to the greatest practical degree. You DON'T just pour concrete on a hot and windy day and say "Oh well, it will probably be wrecked by excessive drying. Even on really large projects like highways, they have weather watches for rain, wind, temperature both hot and cold, they spray on curing compound, and often they cover with plastic or burlap for the first 24 hours, and even rewetting longer to assure good curing. In precast concrete beams, many are cured in conditions totally unlike what they will ever see in the field. The idea is to build strong concrete in the first place, and that means controlling the environment during the early curing process.
I will stick with wet pour. With a dry pour, you have no way of telling if the concrete is completely set up throughout the material. You would have to do a core sample to get an accurate result. This would be like case hardened steel vs. tool steel. Tool steel is completely hardened. Case hardened steel is just hardened on the surface but soft at its core. I see very few aspects where you need to use a dry pour.
You need a crush test, or we know it as a cube test, I’ve never seen a PSI test done and can’t really see what benefit it has, only a crush test will tell you if the size stone + cement + slumb (wetness) will hold up
We do 2 or 3 standardised test cylinders. 6 inch diameter, 12 inch height, for each pour. A nearby engineering lab does the crush test. We never failed a test.
Who needs accuracy when you've got a difference like that. Besides, we all know that unconsolidated dry pour is going to have a much higher air %. Which = less strength.
The wet pour test must consist of the slump, which is the amount of water used and is a measurement of how stiff the concrete is when placed. Look it up.😊
I would always do a wet pour. For small projects, like this pad, mix manually. For something a bit larger get a concrete mixer. For any large slab or driveway, get a premix truck with a slide or pump. Check the slump, also test your own mix quality with concrete cylinders submitted to a lab. I would not trust dry mix to perform consistently, but our own wet mixes have always performed as expected in tests and on site.
Chris, Slump tests? Compression cores? Lad, we did that when repairing dams! I know you don't thing you think that is necessary for a chicken coop slab, so I'll assume you, like most pros, are completely missing the point. Envision, if you will, a DIY couple that has never so much as built a picnic bench. (Call to the local batch plant) "Send me 2.75 yards of 3500 psi, and we're gonna' wanna' 4" slump. What? Do I have somewhere to dump any leftover? Why would there be leftover? Unh. Have to grade the base, huh. I did--sorta'. Better make that 3.25 yards. What? OK, make it four! Don't wanna come up short! Huh? Uh, no, you can't get that close. A wheelbarrow? I can get one. Of COURSE I can push it. I'm in good shape for 72! 800 pounds? Really?? I'll get a little wheel barrow. Who? Oh, it's just my wife and I. First time for everything! Of course I got a screed, I ain't no dummy. What's a float? No! A trowel?? For what? I told you I got a screed! No, I don't wanna send a sample to the lab!! Are you laughing?" OK, THAT guy can dry pour a slab for his chicken coop, dumping bags from his pickup, with a 3" PVC pipe screed, and a garden hose--and have FUN doing it. If he comes up short, he grabs a few more bags. Any "leftover" he takes back. If it takes 3 days, it takes 3 days. It will outlast him and his chickens. And he done it hisself! Yup.
@@FisherCatProductions why can't you just dump the water in and mix it there? True comparison is a half arsed mix vs a dry pour I'd think. The thing that shocked me when I had a slab poured, I asked if they do waterproof concrete for my subfloor and they said, sure, but it's expensive- but it was pennies more and meant no tanking or anything needed. My dad's a chartered builder and we hired a bunch of young landscaper muscle in winter to wheelbarrow it in a rota. They were exhausted but the concrete guys were happy. I'd go for a mixer delivery every time- they even have ones that it only puts in the water at the end now so you can even deliver to old gerald for his chicken coop and doesn't bugger a mixer.
Well. I think it comes down to people doing it correctly. I am sure there are people who cannot/do not do a dry pour the same as the people who cannot/do not do a wet pour correctly. Though a wet pour is a little harder to mess up ( not impossible) so which ever anyone choses to do they should do some practice sample runs first
As a Journeyman Cement Mason I think that you're allowed to do whatever you want as a homeowner. If you think you're saving a ton of money by avoiding professionals and "dry pouring", go ahead. But there are a host of issues that come with not properly mixing concrete. If you don't care about quality this is the way to go! These videos irritate me as someone who's in the industry, but hey to each, their own. You should try making a cake without mixing the batter and let me know how that goes. Might get something close but it's not what it was meant to be. WHY SPEND THE MONEY ON CONCRETE AND USE IT THE WRONG WAY?
these type of pages keeping work going around for all us professionals into the future. a bunch of “well i thought i could fix it after i watched this one video that made it look easy” clients.
I have poured as a homeowner, it amazes what people will do to get out of a little work lol. It is not that much effort to mix concrete. Even if it is a small pad, it is very cheap to rent, or even purchase at harbor freight a drum mixer.
As an Apprentice Cement Mason, I think you're totally missing the value of this man's advice! If people follow this guy's advice, it'll lead to more botched concrete projects that we'll have to fix. THINK OF THE MONEY WHEN PEOPLE REALIZING THRE'S A REASON IT COSTS A FAIR BIT!
These are the other half’s that were left over from the larger slabs I cut in half. I drove over those pieces and smashed them with a hammer. Check out the other videos
@@FullSteamDesigns This has been an interesting distraction for me. When my mind wanders it goes to solutions or how to try the next thing. Recently my mind went to packing the concrete mix with a vibratory flat bottom packer. I noticed that wet pour condenses the material down to a lesser volume than the dry mix. It would be interesting to see if packing it would make any difference in strength. If you do any more tests I would love to see the results. So far so good. I appreciate the time you put into supplying this info for the rest of us out here.
My takeaway is - so the payment for a massively easier undertaking is only a 20% reduction in psi - SOLD. Going to dry pour my shed base now for sure. It's for parking mowers and storing rakes and cushions, not holding up a semi.
The test has a 25% plus/minus accuracy and he's only testing the surface which is where the water enters from, meaning the mix is different from top to bottom.....The middle could be dust and that thing won't detect it.
@Scott-ib3tm Except it's not "massively" easier. Maybe for a small square patch you can reach across, if we ignore you have to go out and keep checking and watering it. I'd much rather level wet.
@@Scott-ib3tm great for tiny projects.. but a lotof projects it's silly to buy a bunch of relatively expensive bags vs. having a truck come in premixed. Huge time (and back) saver if you're time is worth money...
Plus it only takes like 60 seconds to mix a bag of concrete? Maybe 2 minutes? And you could even mix it in the dirt hole and get a 90% mix instead of 0% mix
@@bigrig0625 please every should pour like this. Its super cool, just call when you need to replace any concrete guy will do much better job, get over it little brokie
There isn't enough data in existence to convince anyone who's dead set that one is better than the other. Choose whichever works for your project and your budget.
... still would recommend making wet pour since you never know if you want to do something else with the area and slab.. even if its just 1/4th difference, it matters when you push the limit.
As an American concrete aci certified concrete field tech, you need break tests made in cylinders that get crushed in a lab to get a real idea of concretes strength.
When I do fence posts, I put some water in a bucket and then add the concrete. By the time the hole is dug the concrete is ready. Just tip the bucket and you're done.
Flip that block over and test the bottom. Then crack it in two and test along its whole thickness. I don't think that your psi measurement will be consistent throughout. But the wet sure will be.
@@user-gx1yz8ny1l no sir do not send him back to school, what he needs is some real life hands on in the field training, seeing all aspects of the work involved in the project he is designing.
ASTM 39 is the standard used to test the psi strength of concrete by applying measured force to a cylinder shape of cured concrete and has been for over 80 years. That’s the test the industry and manufacturers use to determine strength of their mixes. Nearly 40 years in construction and I’ve never seen what was shown here to test the compressive “strength” / psi of concrete. JS The biggest problem I have with “dry pour” is the lack of control over the surface texture and porosity. The amount of finishing passes via troweling either leaves the surface porous (screed and float), or harder / closed by more troweling, which makes the concrete surface far more durable. Obviously if it’s simply placed dry and water misted over it, the mix and surface will remain “open” and more susceptible to wear.
I don't think they would recommend something that could be misinterpreted, as this could lead to legal issues. There are good ways and bad ways to dry pour.
@@maxgood42 The only good way is fence posts that are always in the ground. Anything else is just a poor reproduction in comparison. It may hold what you ask of it but it will never be as strong as it was meant to be.
@@archael18 Yes application matters so if a bag had dry pour instructions on it then this maybe used in a way that it would not be safe, so yeah fence post or light traffic areas in less extreme environments and loads. But not if you need it to spec. Also the way it is watered can have different results.
Hahaha just so they could charge you more lol let's not lie here the whole dry pour thing is just a marketing campaign they have been fairly honest on so far... By honest I mean not saying anything about it
@@josepascasio3793 neither will be an issue. Im going to just walk on it. It's a sidewalk path connected to the side of my driveway. And I live in Texas.
Been doing mud beds for over 30 yrs dry method in showers with bagged sandmix. Just add water when your pitch is close and then get your pitch perfect and add water again. Eliminates premixing of mud bed outside of shower, much easier and a lot less labor.
Okay I’m just throwing this out here because I slightly remember reading about it. But alot of the old Roman concrete buildings that are still up today had dry- un mixed concrete in it. Whenever the concrete would crack the dry concrete would weld repair the crack with the outside moisture. You can fact check it, I’m sure I’m wrong on somethings but I do remember that part and thought it was interesting
With all due respect, cement mixers are cheap, and you can mix it with a shovel. On the flipside, you can dry pour a driveway just fine. Concrete contractors have enough industrial scale projects to 'protect their industry' where sprinkling water for many days is too much work when wet mix goes off in a few hours. The ones with opinions have seen it fail, as freezing is usually a big threat to dry mix. If buried as a post it never freeze cycles, and has minimal force on it. It's a bit of a waste of money not to mix it in my opinion, but its your concrete. Also you get more blowing about, concrete powder can blind you and cause lung diseases, so be careful with it.
Honestly, back in Washington we never bothered to even wet the concrete when pouring pilings for pole structures. The moisture content in the soil was more than enough to activate the concrete. We’d just make them half again the depth we needed and call it good.
Our surveyors always used wet 'crete to permanently set their pins. They were very skeptical when we helped by setting them in dry Sakrete as they went along. They were believers when they had to move a few of them a week later, and had to bust them out with a sledge hammer.
Pretty straightforward. Dry pour is probably fine for a lot of things. But wet pour is going to be more consistent throughout by nature and therefore probably better for "harsher" conditions. But you don't need perfect concrete for most small home projects in non-extreme weather. Good stuff.
If you want it to still be there in 5 to 10 years without needing replaced, you are doing yourself wrong, trying to dry pour a 4 in. or thicker pad. It will not hold up. Maybe, sometimes under perfect conditions, people will have good luck, with it sufficing but it is definitely a toss up and is equivalent to not having the clay and limestone mixed properly before calling it Portland Cement. I mean you can cut a hole out of a shoebox and call it a birdhouse too...
Whats the point of testing anything then? Just do everything the way it's always done forever and never learn anything new you seem really clever and creative and fun 😂
Who else thought that the big ass needle he had in his hand was gonna deliver psi hits on increments of 100psi till we found out when it busted the slab 😅😅😅
There's several parameters that determine the strength of concrete. 1. The amount of cement that is put into the mix. Most concrete is 5 sacks to the yard. Government standards are a minimum of 6 sacks per yard. 2. The amount of water is also important. The water in concrete doesn't evaporate, it stays in the concrete forever. The more you put in, the weaker the concrete. 3. Temperature during the hardening process. Keeping the concrete cool during the curing process will increase the strength significantly. However, Don't ever let it freeze, it will be garbage.
Wet pour is 10% as strong as concrete with caged rebar. Do you need "that much?" You use what is in scale to the project demands at hand. Whichever you use....rock? Dry pour? Wet pour? Reinforced pours? Make sure your yields supports what tasks it needs. Good video
no it's not because there is no added labour cost to wet pour. you can litteraly just mix that shit in a bucket in just a few seconds and you get a much better results. there is no application for dry pour because there is no added labour to wet pour while wet pour is 100x better meaning you are actually wasting time and energy on a interior result.
@savagememes873 no added labor to wet pour? Your joking right? Yea you can just mix some water in a bucket but do that 47 more times to get the amount of concrete you need for a project vs just dumping the bag an screeding it an tell me it doesnt add more labor lmao
I don’t know why we are simply looking past that the dry pour has no entrapped air, and if you live in a climate that drops below freezing at any point, it will be pulverized by freeze thaw
What is the debate between these two methods? Isn't dry pouring worse in every way? Doesn't this PSI test only test the top layer? How reliable is it to soak concrete several times just hoping that everything gets wet and forms solid. I can't imaging this dry pour method is reliable at all anywhere the ground reaching freezing temperatures. I'd imagine if water is able to soak through the dry pour method enough to wet most (if not everything) then rain and whatnot could also soak in to the cracks, freeze, expand, and destroy the slab very quickly. Dropping a hammer or something on it too, the solid slab should displace the force and result in chips and whatnot, while the dry pour method would theoretically not displace the energy evenly, resulting in cracks right? It just seems assbackwards, you wouldn't put cake mix into a pan, spray it with some water, and bake, that'd result in a dogshit cake that's not cooked right.
You need to Make you own judgment on this. No one said dry pour better. But dry pour saves you a lot of back breaking labor . If it's just a basic back fill job say thing like raise floor 2in for laying tile . Is that really necessary for me for put in 2-3X extra labor?
I get the feeling that the time some people spend wayching these videos to justify their decision to dry pour is less than the extra time it would have taken to just mix the concrete normally
The man could say " for small home projects" 9000x times in this video and mouth breathers would still complain in the comments i swear concrete guys must have a hole in their heads 😂
That extra 25% strengh is important to me. Also so is rebar. I break things, if you think i cant accidentally break a slab, youd be wrong. My work experiments have damaged steel plates
It always depends on the application. Do you need to handle lots of weight (e.g., for the foundation of your house)? The wet pour is the way to go every time. Are you using it to pour a little slab at the back door to keep muddy footprints out of your kitchen? Dry pour is fine.
