The TRUTH About Dry Pour vs Wet Pour Concrete!! Strength Test - You WON'T Believe the results!!

Geotechnical engineer here, my last job was in airport pavements. We test both new and existing pavements when performing construction and evaluations. There are some less industrialized countries that will dry pour patches, I’ve cored and performed split tensile tests on tens of thousands of samples, the dry pours were always laughably poor quality.

I am a concrete engineer. No matter what, dry cure concrete will always be considerably weaker for many reasons; however, you can increase the strength by keeping the slab flooded with water and covered for at least a week. It would be better to flood and cover for thirty days. No matter what you do, it will not ever reach even half the strength of wet pour concrete!

This is why the teaching of basic science is still so critical.

I'm a civil engineer. We learned 40 years ago that dry pour concrete will always be very weak compared to a cured wet pour concrete mix. The difference can be 10 times stronger for wet pour, and the dry pour will have many pockets of weakness, the wet pour will be uniformly strong. Not a surprising outcome.

In the 80's we would use drypour for building decks and fences, it saved time. Then in 86 I got a job in the local cement plant and at one point worked in the lab. Cement is made by cooking limestone/marble, iron, shale together into clinker. Clinker is then cooled somewhat and ground down into a powder finer than face powder, at that point it is called cement. When you mix cement with sand and aggregates(rocks) it is concrete mix, add water and it becomes hard and is concrete. What happens when you add water is the cement powder crystalizes. This fills tiny spaces between rocks and sand and other crystals, bonding and putting pressure in all directions and during this phase change emits heat. Once the phase change(curing) has gone thru 3 days some 80% of the strength is there, some 3 weeks later and it is at 90%. It never stops curing. HTH

Was really considering a dry pour for my shed build but after your video I'm sticking to the wet pour. Thank you it was a very educational video.

I’m in concrete many years and definitely knew the results even though I have never done what you did to test it, I have my definite instincts that it would be crumbly by what happens to a bag of concrete after it gets rained on. But you are the man! For making a video and doing the test. Bravo 👏

I didn't have any plans to use dry pour, but thank you for providing me with armour against anyone trying to persuade me that it's a good idea.

Thanks for doing this. I've responded to some of these DIY dry pour videos. Concrete curing is a chemical reaction that is dependent on the proper ratios of concrete mix and water. The chemical reaction bonds the concrete particles and stones together by generating heat that is uniform throughout the slab (as long as the correct ratio of water is MIXED in) and is critical to the slab reaching its potential PSI rating. Dry pour, even under the best circumstances, will only ever reach a small fraction of the mixes rated PSI.

I’ve been waiting for a pressure test on dry pour. Thanks!

I feel vindicated and consoled after watching videos of other people "proving its the same" and me knowing down deep in my soul that there's no way a dry pour would be structurally sound. Thank you.

I'm glad to see the experiment completed, but can't see how anyone would have predicted a different outcome. The strength of the concrete comes from the cement and water being mixed in and helping everything stick together. There's a reason why you don't see manufacturers recommending it. Dry pour concrete is like baking a cake without mixing the ingredients together. You get similar undesirable results. Thanks for demonstrating what a bad idea this is.

Thank you for definitively proving for us what I had always suspected. Great video.

Awesome video and you got yourself a new subscriber! I was going to do a dry pour for my backyard slab due to all the Youtube videos on dry pour. Thanks for saving me

Thanks for ray, honest reveal and test of both dry pour and wet pour concrete! Great job!

I worked as the QC in a precast concrete factory many years ago and later studied civil engineering. I literally had no idea anyone would 'dry pour' even a basic concrete slab due to the inherent weaknesses highlighted in this video. Thank you for the video.

There's a reason no professional concrete finishers do dry pour, you wouldn't want mortar or grout that had moisture in it, if it cures at different times as in some parts were exposed to moisture in the bag and were lumpy while other parts were dry powder they would not bond right. You are essentially drying it in layers that will not bond together correctly and the first layer will somewhat properly cure while shielding the center section and bottom from getting enough water to properly cure.

Thank you I’ve always wondered about those been interested in the results. Very informative thank you.

wow thank you for taking the time to fill the internet with real information! priceless

Great video! I watched a few of the dry pour videos and figured it was the easy way to do an inferior job. BTW, please wear a respirator while cutting concrete. The powder causes major problems to your lungs over time.