Concrete pores | porosity permeability
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- Опубліковано 8 вер 2024
- The size, distribution and shape of pores determine how easy it is for moisture or gases to move within concrete. Movement of fluids are critical for the durability of concrete. The concepts of porosity and permeability are defined and then high resolution nCT scans of cement paste are shown. This allows the concepts to be theoretically presented and then examples of actual pores are shown. This makes it easier for viewers to not only understand the theories but then also understand how to apply them to improve concrete.
Thanks to Hailey Goodale! She edited this video and is my Director of Awesome.
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One of the best teachers I've seen in my life. Thanks sir.
Tyler, you are one of the best. This was another great video.
You're a teching beast, Tyler, your students are so lucky to have you!
Thank you so much Nicolas!!!
Always love the energy and enthusiasm you bring to your videos. Keep up your good work.
Your the concrete guy thanks buddy
Thank sir, your knowledge about concrete so deep
Amazing how you define with experience and enthusiam porosity. Obvious it is not only like what many describes like the amaunt of concrete potres and cavitis by defined as a percet - age of total volumen metter. Who like conret you have is simply right Videos 👍👍👍👍
Thanks for the video. What is desired in concert, high porosity/permeability or low. Also wish you do video on requirements for concrete longevity. I have 15 years old concert beams that were made from 3500psi concrete from a major readymix supplier, but show concert chunks peeling off showing the steel bars. At other places I see 50 years concrete including bridge columns in the sea and still solid and intact. A video about the basics in how to make long lasting concrete structures will be helpful.
Excellent explaination on voids and porosity
I just aquired a house built in 1923 that was my grandfathers. He purchased it in 1958 and at the time, it had no basement. Over 5 years or so, my grandfather dug out a basement and built cinder brick walls to support the house as well as poured a concrete floor. The land the house is built on is heavy clay with mountain stone as an aggregate. When he poured the concrete floor, he poured the concrete directly on the compacted clay he had dug out. The floor is solid and has no cracks that are visible, but this basement has always been very damp. I have a very strong suspicion that the concrete is pulling the moisure out of the clay under the house via capillary action. There are visible damp areas that sometimes pool in the middle of the floor in the spring when the ground becomes saturated. In fact, I beileve there may be a spring at one location as it becomes damp and visible wetness on the surface with moderate rain fall. My question is how do I stop this capillary action. Typically, stone is placed over the ground and concrete poured over to break the capillary action, but I do not have any, concrete sits right on the clay. Is there a way, or some product that I can pour on the concrete over the entire floor that will soak in and stop the water / moisture from coming to the surface? I have heard of products that you apply to a surface and they soak in and alter the chemical composition and block the pours with growing crystals and these crystals propagate everytime the concrete is exposed to water. What is this product? Does it work? Would you recommend or what would you recommend?
Two examples of these products are: www.accuflexcoatings.com/crystal-matrix.html and www.master-builders-solutions.asiapacific.basf.com/en-asia/products/masterseal/masterseal-501502.
Another that seems to be available to homeowners in my local area. www.lowes.com/pd/Ghostshield-Clear-Flat-Flat-Concentrated-Waterproofer-Actual-Net-Contents-128-fl-oz/999911193
Check this video out:
ua-cam.com/video/AXvWlMfQk_4/v-deo.html
I would try a silane and see how it works.
@@TylerLey Thanks for the reply. I have watched this video and several others with associated topics such as your video on Surface coatings and sealers. Good Stuff. I want to be sure you understand that my moisture issue is from beneath the concrete and not on the surface. Will your suggestion using Silane product still achieve what I need? The concrete was poured directly on dense clay (I know, much less than ideal) and living on the side of a mountain provides ground water from underneath the house and then is pulled up through the concrete and makes the floor (and basement) damp all the time. In the spring when the water table is high, water has actually pooled on the surface in the middle of the basement floor. (No cracks visible). Should I still try the Silane?
epic teaching method 💕
great video bud!
Thanks a ton Tyler. You're the man
Thanks Dr.Ley!
So great visual aids, omg! Just subscribed to you.
I have a question though. Your example is just one day hydration, and that as more water enters the voids, more hydration process is going on thereby closing the pores. But how can hydration still occur (after one day) if there's only water and not any cement left since all of it has been used by the previous hydration? THanks ::)
Awesome video! Thanks!!
Thank you! You just dont find it explained so detailed on the internet like you do here. I find it hard to understand the structure of materials unless I fully know whats going on down at the microscopic level.
I have the same issue! Thanks for the comment!
because of u dr tyler ley I became concrete freak
u made me concrete freak
Great video Tyler. Thanks for sharing. It would be nice to know what to add the concrete to avoid gigh porosity. My concrete keeps cracking every winter. It is awful
good job mate
Explanation on Strength porosity relationship in concrete please sir!!
Amazing ,thank u so much.
Thank you
Love you bro ...😘😘😘😘
Hi Tyler, would it be possible to design a low permeability mix with low mechanical strength (in the CLSM range)?
Wow Tyler, I have just found your channel and been watching your videos for hours!
This one is awesome but I am wondering about the capillary suction. As these tunnels get smaller (but not closed off) is the capillary suction not going to increase? Furthermore, I know that the main feature of an air-entrained admixture is to increase the freeze-thaw resistance of the concrete but would it not decrease the capillary suction on the other hand (air bubbles would break the continuity of the "tunnels") ? I am thinking of adding an air-entrained admixture to the concrete in an environment where capillary suction of the moisture measured in years is the main problem. Do you have any thoughts on this? I know this is crazy because this is not how everyone uses air-entrained admixtures but you are an air-entrained concrete guru given your PhD !
Hi Tyler, is dry casting more porous than wet cast. Can I drycast in situ footings and columns?
you are wonderful
absolutely u are carzy in concrate
thanks so much for the video.
can you give as examples for the
relationship between water cement ratio and grade of concrete.
Mohamed - It depends on how you define your grade of concrete. Most building codes define grade in terms of strength. This is a little challenging as strength will depend on a lot of different things and w/cm is only one of them. Your aggregates and the amount of cement paste plays a big role in the strength.
Here is a very practical answer that dodges some of the details:
0.50 w/cm - internal concrete that will not be exposed to the weather
0.45 - external concrete in a moderate climate
0.40 - external concrete in a severe climate
In all cases, I would use an SCM. If you have concerns about freeze-thaw durability then I would air entrain.
You can learn more by watching this video: ua-cam.com/video/S8oc4rsleAY/v-deo.html
I wonder the affect of tensioning the concrete has on the pores if any? Generally you’d wait till the concrete would get to strength, but it would be interesting to be able to see the difference.
Thanks Matt,
Early loading of concrete might cause cracking. These cracks would really impact the pore system and how outside chemicals would enter concrete. Cracking is a big deal and I have a bunch of videos about it that I have made. Here is one of them:
ua-cam.com/video/1ELHzXuwdqg/v-deo.html
sir, please tell the journal paper where this method used to measure permeability
HiTyler, Can anything be added to a concrete mix to add more or better hydration to decrease the premability between pores?
What about a chemical manufacturing plant? Any standards or special regs to prevent hazardous chemicals that were accidentally spilled from seeping into the soils and/or groudwater through the permeable pores? THANKS. ~Bruce
HinTyler, I’m wondering in a basement wall application shouldn’t we make the outside concrete wall have some type of membrane or Polyurea applied to have no moisture wick through and if it cracked no water with ever go through it?!?
And if I insulate my concrete basement walls with polyurethane with Polyurea on top is the concrete going to crack for lack of moisture?!?
I’ve heard some companies use a crystallized protection that wicks through the concrete wall and makes it non porous! Is this also a good thing or my other systems I mentioned above better?
Thanks
Hello Professor,
What kind of test is done to check the permeability of fly ash concrete?
Amazing sir
Excellent Video...Big fan of your videos!!!
The high-tech nCT 24 hr scans are awesome.
Are there any discernible voids remaining after 3 days? 7 Days?
Blaine - This is a great question. We don't have scans at these ages at this resolution. We have scans at more coarse resolutions and we still see pores. They do decrease over time. It would be awesome to do the scans with the nCT on the same hydrating sample. Stay tuned!!!
I am particularly interested in this subject of porosity/permeability because a company I am involved with is developing concrete additives using cellulose nanocrystals (CNC). One of the hypothesis to explain its significant effect on both short-term and long-term strength (flexural and compressive) is the theory that CNC may be creating a hydration path (perhaps temporarily) via short-circuit diffusion enhancing hydration of cement particles. Perhaps an off-line discussion is in order as this is a very narrow subject.
Please continue making your awesome videos.
Hi does anyone know if a more permeable concrete mix produces a denser concrete?
what is the difference between pore size and pore size according to the question what is effect factors for salt crystallization distress?
Hi Tyler, your videos are super duper awesome and they help a lot, but can you PLEASE turn down the volume of your background music or turn it off. It is really distracting.
Thank you.
informative video👍👍👍...what is itz? How to improve interfacial transition zone poperties of concrete...pl. Explain or make a video on this topic, sir...
I made one here:
ua-cam.com/video/iWljfrwAWf8/v-deo.html
OMG 10Q so mach
I started pond curing of slab but after some hours water is coming down with out any cracks in the concrete?.... Can u explain plz
Awesome 😍
Thanks Arvind!!!
thank you professor , i email you but you did not reply PHD candidate from china , Jinan University
Thanks for the video. What is desired in concert, high porosity/permeability or low. Also wish you do video on requirements for concrete longevity. I have 15 years old concert beams that were built with 3500psi concrete but show chunks of concrete peeling off showing the steel bars. At other places I see 50 years concrete including bridge columns in the sea and still solid and intact. What are the basics to
ABC - You want low permeability and low porosity. I have a video planned for concrete service life. I think it will be out next week. The question you asked is very hard but I will provide some insight.
Tyler Ley
Thank you for your reply, and look forward for concrete service life video. It will be helpful if you mention in the video if any additives or specific ingredints must be added to the readymix. and if different weather temperatures require different readymixes, summer vs winter. As the readymix suppliers are not forthcoming with what they can do. They expect the customers to specify.
Actually, I have a question. If water can go straight through concrete, that means that any steel reinforcing bar (rebar in USA) inside would eventually rust as there is now the presence of water against the steel (which also includes oxygen right?)
Water takes time to go through concrete. Also, water by itself will not cause corrosion because of something called the passive layer. Check out a video here:
ua-cam.com/video/BqpLDm_InQg/v-deo.html
Cool
👍👍👍
Professor,
Please suggest me a suitable test for porosity quantification in concrete. My concrete with Microslag and GGBFS. I tried with MIP. But when I am comparing the diffusion coefficient with porosity of these concrete, I could not find a strong relationship between them. What about X-Ray Tomography??Is it give more accurate idea about porosity than MIP?
Kiran,
MIP has lots of problems with it and I wouldn't recommend it for concrete porosity. I would use dynamic sorption isotherm. Send me an email and I can get you a paper over it.
Hello.
You're the Man Tyler. Red Pill power. Can you please address Liberal Psychosis.