Been wanting to learn about all aspects of concrete & today, I joined Ley Concrete Institute. Glad to have found you & your channel because you are certainly "ley"'ing it all on. Thanks for sharing!
Thank you for this lesson! I liked your explanation of the Max Nominal Sizes. From 15:37 It helped me understand why it says "90-100 passing" in the table, it's because 10% include the max size aggregates retained in there.
There was a company in Bucks County Pa that supplied sand,stone, and ready mix concrete called Warner. They mined most of their aggregates from pits near the Delaware River. It was all very rounded natural stone. I have no idea what the mix was or anything but it was some tough concrete. They were out of the ready mix business probably around 1970 when I was just a kid, but whenever we came across their concrete on a job and had to break it up it was tough to demolish. I remember one job back in the late 80's removing the bases of smoke stacks and our operator pounded on them for what seemed like forever with a 5 ton wrecking ball before they broke up. Even the sidewalks where I saw that aggregate were hard to break
@@TylerLey Do you think the aggregate is what made the concrete stronger than what we normally encounter? Typically what I see looks to be nothing but sand and crushed 3/4 stone. The Warner concrete had a wide variety of stone sizes in it.
Dr. Tyler, would be useful for contractors if I made a facility that uses multiple sieve sizes to separate the aggregate by size and then remixes them to order?
Thanks Tyler for putting this series together, I learned a lot of the lingo and understand some of the forces of making better concrete. I want to cast a privacy (non-bearing) wall out of large aggregate (6" round-like granite fieldstones). Is there a formula for how to graduate the mixture down from 6" rocks down to gravel and sand / cement to make the well-graded aggregate / paste mix?
Did you review the core sample report, just released from the collapsed Florida Condo? It looks bad. It appears the cement has turned into powder. Let us know your findings. Great job!
Hi Tyler, Great and very informative videos. I have a simple but I think interesting question for you. How much moisture content should we include and allow for within aggregates including sand in our mix design? This is important in my opinion because it can throw out the W/C/R if not calculated for in the design.
Jon - Good question. It depends on the moisture content within the aggregate. Usually, we have to measure this and correct our mix for it. I talk about it in these videos. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-hnYopL7uZE4.html&t ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-8t1tIpsLvc0.html
Jon, unfortunately we don't tell aggregate how much water we should allow for it, it tells us how much it has! I've seen sands that have 6% moisture. To put that in perspective: a yard of concrete might have 500 lbs. of cement in it and 1,400 lbs. of sand (totally arbitrary numbers). 6% of 1400 is 84 lbs of water. If our mix has a .5 w/c ratio, that is 250 lbs. water TOTAL (including moisture in the aggregate). The 84 lbs (plus whatever is found to be in the coarse aggregate) has to be subtracted from the total. If you look at a batch ticket from a ready mix plant they often give you design water (250 lbs) and Water Added (250 - 84 - coarse aggregate moisture). Moisture is so variable (even going from one part of the agg pile to another can have an effect on the same day) that it has to be monitored constantly.
This is a really complex mathematical problem (IIRC the Kepler conjecture?) that is masked by decades of experimental data and real world results. Its even harder since the aggregates have random shapes instead of spheres. I did find a couple of papers that used Monte Carlo style simulation to determine optimal sizes/ratios for non spherical aggregates. Packing of non-spherical aggregate particles by DEM By Piet Stroeven and Huan He And Optimization of A Computer Simulation Model for Packing of Concrete Aggregates By ADIL AMIRJANOV and KONSTANTIN SOBOLEV Something for an upcoming PhD student to consider.
Dr. Ley, pls kindly tell need how to make concrete for a 10 Bay garage for fixing cars and semitrucks. Appreciate your answer, Thank-you so very much!! Also, need it in 2 days as well if possible, gratefully, Dave
Hi Rob if you have the time I would like some advice please. I’m looking for a claylike concrete to apply to a form. I would like to pack it by hand to be between 10 and 20mm thick and would like it to have the same strength properties as fibre cement board. I know it’s audacious of me but do you have a recommended recipe? I am in South Africa but I have access to Chryso and Sika. I will ask them for advice too. It’s for a home renovation. I would like to make a fancy window frame type thing for my parents.
@@TylerLey Keep up the good work. I met a gentleman last summer who was a professor in Dublin, Ireland while he was visiting Stanford as part of his research into creating environmentally-friendly concrete. He was a little embarrassed to start the conversation with the statement that his research was in concrete, but I just zoomed right in with interest. Good times.
I must admit, I learned something in this video about the rules of maximum aggregate sizes! [not that I have not GROSSLY violated them in the past! ~( ,m,)~ ] (On one project I chucked a few large whole rocks into the form before to stretch my concrete, but the wall is only 24 high and was 10 inches wide, so it went okay for the purpose intended, it is not load bearing nor a retaining wall).
Hey Tyler I am making cement pot plants small ones about 10cm high they are cracking. What do you recommend with the mix and I also want to achieve a smooth finish would be much appreciated if you can get back to me thanks Rob 👍
Tyler - I'm no Tyler but I did write an article for the International Concrete Repair Institute's magazine Concrete Repair Bulletin (Mar/Apr 2019) titled 'I Wanna Rock! The Significant Role of Aggregate in Creating Great Concrete Repair Materials' It's a simpler version of what you are presenting. One interesting thing I found based on aggregate volume : surface area ratio. Of course going larger on the coarse gives you higher slump, everything else being equal. However that slump benefit diminishes once you get larger than 3/8" MaxNom since the V:A ratio converges pretty quickly at larger sizes. Do you agree?
Thanks for the comment. Shoot me the article offline I would like to see it. I have not done a lot of testing at that low of aggregate size. I can say that there doesn't seem to be much difference between 1/2" to 1.5". I think the surface area is important but there are other things that are more important. I can send you some recent journal articles that we published that gives more insight. We are also doing a ton of work on manufactured sand. It has really opened my eyes on sand and how it impacts workability and performance of concrete. I think we will have some tools that will really help the industry.
I didn't get the last few minutes - min dimension/cover - is that by volume or total width? 3/4th of what? Let's say my wall is 6", and rebar size is 3/4th inch. What should be the aggregate fill?
It depends on how much mica there is. Mica can have a lot of reactivity from ASR. It is also not a very strong material and it cleaves easily. However, it might help you reduce your modulus which might reduce your cracking. Do you have any experience with it?
It makes your concrete more glittery! I worked for a a large manufacturer of cement based tile thin sets and grouts (one of the well known names). It seems sand in GA, where one of our plants was located, has a bunch of mica in it - an amount that is noticeable to the eye when looking at the grout. I once got a call from a customer - Something's wrong with the grout, it's not as shiny as usual. He had gotten product from a plant in a different part of the country.
@@mohamedabdelalim896 my idea was to use fine basalt sand as a substitute for river sand in concrete for greater rigidity my idea is to use 1 part of the cement 1.5 parts of large basalt sand and 0.5 parts of fine river sand for better filling of cavities.
Goce Kocov well, I hope we can be in touch and go for further discussion about different problems in Concrete, here's my what's app number for better contacting, thank you in advance dear friend, +201149391735
This video should be linked to a on-site concrete laying video with wall & slab form techniques simply to show what you mean. Students would link it all together more quickly. Great info as usual.
Honestly a lot of what you were saying about the same mix is hard to understand what you mean. If a mix is different its different. Can be the same and different. When i listen to this i think about the fact it would take years to even explain how concrete works. I mix a lot if concrete a few yards or a few dozen yards at a time special mixes for strange micro engineering jobs i get. Walls, underpinning etc. the point is you can not get good concrete in a bag ever. You have to make your own. So ... you have to know how
Very well done but I believe your preschool teacher did not teach you not to say other people's food is " nasty" . Or was it that you did not listen? 😉