6:30 - bouncy houses from hell - that's a pretty good description. You don't know about noise until you have been around one that's running. The Clinker is what you get when you reduce a mixture of limestone, marl and silicone sand in the right proportions. (crudely stated) and you usually burn coal to do that, but I have heard about considerations now to use electricity. There have also been trials using pure oxygen instead of air to burn the carbon. A consideration from my part is if it would be possible to heat-dry a proportion of the limestone to drive out water from it before adding it to the mixture to further reduce the shrinkage since it's well known that burnt lime expands when getting in contact with water. It would of course contradict the energy saving, but not make it impossible since there's a lot of excess heat in the cement producing processes.
Hi Tyler, your video was fantastic congratulations. The use of limestone is great I have used it I all my mix designs, I usually Packing Model particles below 100 micro meter , so it can to use more than 12% of addiction and have a performance even better results.
I have worked on External Sulfate Attack on PLCs, upto 20 percent. The results were a bit confusing, especially for strength reduction. We found reduced ettringite expansion over 12 months. We also used a small dosage of dolomite in it that works better then calcitic limestone alone. Yes, we observed mono and hemicarboaluminte formation between 8 to 15 degrees in 2-theta angles, that's something is reffered as ettringite stabilization. My questions to you: - did you use commercially made Type IL or it was separately blended? - Did you study the changes in porosity over a certain hydration period? - What is the reason of low drying shrinkage in your study?
Thank you very much professor. Fantastic video, I like it. Actually I'm a postgraduate student and my research is about producing self consolidating concrete utilizing limestone powder. Until now, the action mechanism of LSP is dilution effect. I thought that could be due to the surface area of LSP is less than cement particles and the chemical reactivity of LSP is lower compared to cement. I'm so excited to understand the concept of nucleation effect. Thank you.
thank you for these great videos. i have been in readymix concrete business for 24 years and our company switched to 1l or Il cement a few months ago. our finishers are having issues with shrinkage cracking since the switch especially with type c flyash. strait cement is not causing cracking issues. they pour on 5-7" slump is this cement more sensitive to w/c ratio? I am trying to find answers to this situation to help our customers with this. i already working on them to pour closer to 4.5-5" slump. thank you.
I use Portland cement every day to make Parking Blocks and Cement sign post bases. in the one major thing you did not talk about about these changes that they are making to the cement is how temperature affects the curing basically if it’s below 50 degrees temperature the cement will not cure properly this has been a major problem for me in my business! Basically if I use 6-94 pound bags of type 1IL Portland cement with 1- yard of aggregate If the ambient temperature is below 50° it will not cure properly and the CONCRETE will never gain strength after that
Hi Tyler, love your channel. I've seen numbers closer to 8-10% of global CO2 emissions (Chatham House, 2016) with 90% of those emissions attributable to clinker production alone. Whatever the exact numbers, they're huge, so I applaud the emphasis you've placed on SCMs and PLC, etc. Which class of fly ash did you use in your PLC blend? Was that assuming weight-batched 15% OPC prior to replacement? Have you tested a similar PLC blend with slag? Over 50% total OPC replacement would be a nifty milestone. Any plans to discuss geopolymers? Sorry for all the questions my friend. Thanks for the excellent content.
If you had to create a green concrete (sand, aggregate, cement) with an emphasis on strength what would be your mix? Would that mix change if it had to be carbon negative? I’ve seen many sources say plastics and glass can be used as a substitute for aggregate, would you go down this path? Also would silica fume be useful in this process? Why and why not? Sorry for all the questions, but I’m very interested in this topic. Thanks for your help! Feel free to go as in depth as you’d like
Please talk about minimizing Bug Holes, i work in the QC lab in Colorado.. the tests pass to pour, but the pieces come out like crap, honeycombing, spalls, bug holes that would fit a family of bugs.. please, what are we missing?
Dr. Ley thanks for another great video! I have in my notes to avoid limestone aggregate to avoid alkali carbonate reaction but that doesn't seem to be a concern here. Does the increased surface area of ground limestone SCM cause it to react during hydration, leaving it inert for the alkali carbonate reaction? Or is there some other reason it isn't a concern with the finer particles?
Thanks! Please watch my videos on ACR for more details. ACR only happens in certain types of dolomitic limestone. These will be avoided for this type of cement because they will be too hard to grind. Thanks for the question!
Hello Dr. Ley almost always there is a 'but' or exceptions. What would be the exceptions of using this? Is it limited by moisture, since calcium hydroxide reacts with water? Is there information on the strength decreasing after prolonged exposure? Thank you.
Cement is made from limestone, so it's already mined; just not heated. So, limestone is heated and ground, other limestone is simply ground and added without heating.
Can you achieve 5%-8% entrained air? I'm a municipal engineer in Montreal, and concrete exposed the the elements is required to have from 5% to 8% entrained air in order to help resist damage from freeze-thaw cycles. Even that doesn't work, any concrete exposed to de-icing salts will be destroyed (at least the first inch or two on the surface) after about 20 or 30 years.
Does the water demand increase with PLCs? Are chemicals as effective? I’m using 10.5 oz/100 wt (Sika 2100) at a .40 w/cm ratio (SCC mix) I’ve never used this amount to reach my spread.
Awesome video! Going 'green' is great, but hard to convince a client to do unless there is also a cost savings. Do you have a cost comparison per cubic yard or per truck when the limestone is used and not used?
I can tell you the Cement companies are not going to give ready-mix producers a discount for using a waste product in their cement. Costs will remain the same. Plus, reduced performance will require increased dosage of water reducers to offset the loss of cement in the mix design.
Tyler, do know of reports of increased shrinkage with PLC? Asking because I have (informally) found that, even when using CSA cement with a high proportion of limestone powder. That paste-only case had sudden extreme plastic shrinkage. Could be other causes of course. Also found frothing (CO2) when citric acid added at very high dose, but this did go away. I agree that PLC is beneficial, and would like to use it. Just want to know relevant factors. Thank you! Second Edit: It appears that the CSA shrinkage was autogenous due to very low w/c.
You make a great case with your extensive knowledge of all things concrete for these formulations. The merits of PLCs can and do stand on their merits as to performance and cost savings. It is, though, sad and disappointing to see how you have capitulated to the siren song of the "CO2 emissions are bad" crowd. I sincerely and respectfully ask you to properly investigate the truth of CO2 in our atmosphere.
Professor Ley, what would be the w/binder ratio for durable PLC work? Remains 0.35-0.45 as suggested for normal Portland cement? Can we use water reducing admixture as normal and how about the influence of SBR polymeric admixture to the hydration process of PLC?
What is the specific gravity of Type IL (or other PLC)? It should be less than 3.15, and what constituent is increased to compensate for the lower SG? Sand? Or do you keep the SG of the PLC at 3.15 so that the mixtures are comparable as the powder contents are the same?
I don't think there are any concerns. Deicer salts can sometimes attack the calcium hydroxide in the concrete. A PLC should have less calcium hydroxide and so should perform better.
Where can we see the cited sources? Is there update on these? REALLY want to make the case to have suppliers know these options, and ask then to use lower CO2 mix.
I'm planning on making concrete weight lifting plates (450mm diameter) for training at home in quarantine. How would I place the rebar to prevent cracks since I'm going to be lifting and dropping the weights on the circular edge (probably onto some rubber matts to decrease impact shock). Is using 4 pieces of rebar in a Hash pattern enough?
hello doctor Tyler could you kindly write the whole citation of the reference you gave on minute 2:26 (Matschei et al., 2008) i couldn't find the graph nor the paper. I need it for my research
@@TylerLey in our campus our professor did'nt cover our reinforced concrete design course due to covid-19 thats why I am requesting you to... So that we learn from your channel in home
50% portland reduction is no joke. I assume that your building has plc painted surfaces. Any differences with paint or other coatings as far as adhesion? Great video!
I notice you referenced Compressive Strength, but...I've seen a clear reduction is Flexural Strength (breaking beams). The aggregate (crushed limestone) seems to not bond with the cement, much like you would expect if one had used an unwashed limestone. Trying to figure out why the flexural strength is lacking...anyone have any ideas?
What is the percentage of #200 sieve washout in the aggregate after conducting a gradation test? In my experience, the dust in the rock can lead to bonding issues. Additionally, I suspect that the additional limestone may contribute extra dust without providing any beneficial bonding component in the concrete. Concrete can be stronger in compaction and weaker in tension… this could cause worse tension breaks.
**One concept i have been wondering about (and what may make a good video or two), is can non-coal/petrolium coke methods be used for producing some of the materials you mentioned in this video and other (Mainly Fly Ash, Fumed Silica, Slag (Not sure if "Clinkers" are different, but those too) ) ** The main methods are via Biomass and/or Refuse Derived Fuel (or RDF) Plants Many Operate in Similar Methods (or even "Co-Fire" coal (but i hate coal so don't condone the practice, but this is besides the point) ) to Conventional Coal Plants. In some areas they are catching on, especially Europe where landfills are almost non-existent due to policy differences compared to the USA. I wonder with there may be chemical diferences that may make it not work or work differently (as you pointed out with the need for chemical analysis of feedstocks in one video for this exact reason) ?
I think it has promise if you don't need high strengths and you are in a mild environment. You also need an abundance of clay that is close by. I think there are lots of barriers in the US but it may work in other countries.
@@TylerLey Sorry but I had to ask, seems not enough people today ask if the solution to a problem is just as bad or worse than the problem itself. Love your videos by the way!
Why aren't there many songs about concrete: About how to cure and dry? Concrete is a composite, but only reinforced If there is rebar on the inside . So we've been told, and some choose to believe it I know they're right, wait and see Someday we'll find it, the concrete connection The Builders, the designers, and me.
Isn't this just "greenwashing" since substituting portland for limestone is just eliminating the work and cost of converting that limestone to portland?
So many carbon narrative alternatives end badly if you pull the string. For example limestone is cheap, natural gas for kilns is not - why hasn't Limestone been used before? What was wrong with a cheap material back before the climate narrative replaced free market thinking? I think I'm convinced that you CAN add limestone, but I'm not sold on the idea that I SHOULD add limestone.
I have just one request, please never think of stop making these videos 😐
Love from Bangladesh ❤️
What, AWESOME
Ohhh wow, I’m here in Oklahoma as well. Right in OKC. Neat
6:30 - bouncy houses from hell - that's a pretty good description. You don't know about noise until you have been around one that's running.
The Clinker is what you get when you reduce a mixture of limestone, marl and silicone sand in the right proportions. (crudely stated) and you usually burn coal to do that, but I have heard about considerations now to use electricity. There have also been trials using pure oxygen instead of air to burn the carbon.
A consideration from my part is if it would be possible to heat-dry a proportion of the limestone to drive out water from it before adding it to the mixture to further reduce the shrinkage since it's well known that burnt lime expands when getting in contact with water. It would of course contradict the energy saving, but not make it impossible since there's a lot of excess heat in the cement producing processes.
I've heard shop scale ball mills and vibratory polishers, so i can only imagine the noise of industrial scale lol.
Great one!
Thank you!!!
Hey!!! We can't subscribe? You are the best dude!!!!
Hi Tyler, your video was fantastic congratulations. The use of limestone is great I have used it I all my mix designs, I usually Packing Model particles below 100 micro meter , so it can to use more than 12% of addiction and have a performance even better results.
YES 👍
Another great video, Tyler. You are one of the top concrete minds....almost as good as that guy at the University of Arkansas, Cameron Murray.
The company i work for here in Australia are going down this path shortly.
I have worked on External Sulfate Attack on PLCs, upto 20 percent. The results were a bit confusing, especially for strength reduction. We found reduced ettringite expansion over 12 months. We also used a small dosage of dolomite in it that works better then calcitic limestone alone.
Yes, we observed mono and hemicarboaluminte formation between 8 to 15 degrees in 2-theta angles, that's something is reffered as ettringite stabilization.
My questions to you:
- did you use commercially made Type IL or it was separately blended?
- Did you study the changes in porosity over a certain hydration period?
- What is the reason of low drying shrinkage in your study?
Sir your videos are amazing
Thank you very much professor.
Fantastic video, I like it. Actually I'm a postgraduate student and my research is about producing self consolidating concrete utilizing limestone powder. Until now, the action mechanism of LSP is dilution effect. I thought that could be due to the surface area of LSP is less than cement particles and the chemical reactivity of LSP is lower compared to cement.
I'm so excited to understand the concept of nucleation effect.
Thank you.
Thanks Khalid! All the best on your studies.
thank you for these great videos. i have been in readymix concrete business for 24 years and our company switched to 1l or Il cement a few months ago. our finishers are having issues with shrinkage cracking since the switch especially with type c flyash. strait cement is not causing cracking issues. they pour on 5-7" slump is this cement more sensitive to w/c ratio? I am trying to find answers to this situation to help our customers with this. i already working on them to pour closer to 4.5-5" slump. thank you.
I use Portland cement every day to make Parking Blocks and Cement sign post bases. in the one major thing you did not talk about about these changes that they are making to the cement is how temperature affects the curing basically if it’s below 50 degrees temperature the cement will not cure properly this has been a major problem for me in my business! Basically if I use 6-94 pound bags of type 1IL Portland cement with 1- yard of aggregate If the ambient temperature is below 50° it will not cure properly and the CONCRETE will never gain strength after that
Great video 👍. Thank you
I am really glad you liked it.
I don’t know why I’m suddenly so interested in concrete
Love your videos 🧱👍
Hi Tyler, love your channel. I've seen numbers closer to 8-10% of global CO2 emissions (Chatham House, 2016) with 90% of those emissions attributable to clinker production alone. Whatever the exact numbers, they're huge, so I applaud the emphasis you've placed on SCMs and PLC, etc. Which class of fly ash did you use in your PLC blend? Was that assuming weight-batched 15% OPC prior to replacement? Have you tested a similar PLC blend with slag? Over 50% total OPC replacement would be a nifty milestone. Any plans to discuss geopolymers? Sorry for all the questions my friend. Thanks for the excellent content.
If you had to create a green concrete (sand, aggregate, cement) with an emphasis on strength what would be your mix? Would that mix change if it had to be carbon negative? I’ve seen many sources say plastics and glass can be used as a substitute for aggregate, would you go down this path? Also would silica fume be useful in this process? Why and why not? Sorry for all the questions, but I’m very interested in this topic. Thanks for your help! Feel free to go as in depth as you’d like
Good question - I wondered the same thing.
Mmmmm cement
I agree!
Please talk about minimizing Bug Holes, i work in the QC lab in Colorado.. the tests pass to pour, but the pieces come out like crap, honeycombing, spalls, bug holes that would fit a family of bugs.. please, what are we missing?
thanks for getting me through this election!
You forgot DOLOMITE! 🤩
Dr. Ley thanks for another great video! I have in my notes to avoid limestone aggregate to avoid alkali carbonate reaction but that doesn't seem to be a concern here. Does the increased surface area of ground limestone SCM cause it to react during hydration, leaving it inert for the alkali carbonate reaction? Or is there some other reason it isn't a concern with the finer particles?
Thanks! Please watch my videos on ACR for more details. ACR only happens in certain types of dolomitic limestone. These will be avoided for this type of cement because they will be too hard to grind. Thanks for the question!
Hello Dr. Ley almost always there is a 'but' or exceptions. What would be the exceptions of using this? Is it limited by moisture, since calcium hydroxide reacts with water? Is there information on the strength decreasing after prolonged exposure? Thank you.
👍
Hello Dr Ley . I love U man
Sincerely
can u use 20 %fly ash and 35 % slag or just one or the other
And the petrol involved in mining limestone
Cement is made from limestone, so it's already mined; just not heated. So, limestone is heated and ground, other limestone is simply ground and added without heating.
Can you achieve 5%-8% entrained air? I'm a municipal engineer in Montreal, and concrete exposed the the elements is required to have from 5% to 8% entrained air in order to help resist damage from freeze-thaw cycles. Even that doesn't work, any concrete exposed to de-icing salts will be destroyed (at least the first inch or two on the surface) after about 20 or 30 years.
Does the water demand increase with PLCs? Are chemicals as effective? I’m using 10.5 oz/100 wt (Sika 2100) at a .40 w/cm ratio (SCC mix)
I’ve never used this amount to reach my spread.
Awesome video! Going 'green' is great, but hard to convince a client to do unless there is also a cost savings. Do you have a cost comparison per cubic yard or per truck when the limestone is used and not used?
I can tell you the Cement companies are not going to give ready-mix producers a discount for using a waste product in their cement. Costs will remain the same. Plus, reduced performance will require increased dosage of water reducers to offset the loss of cement in the mix design.
20 percent limestone repalacing here in srilanka is it appropriate fo the strength and disability?
what about reactive (heat activated) metakaolin (a byproduct of glass beads production) instead of limestone?
Tyler, do know of reports of increased shrinkage with PLC? Asking because I have (informally) found that, even when using CSA cement with a high proportion of limestone powder. That paste-only case had sudden extreme plastic shrinkage. Could be other causes of course. Also found frothing (CO2) when citric acid added at very high dose, but this did go away. I agree that PLC is beneficial, and would like to use it. Just want to know relevant factors. Thank you! Second Edit: It appears that the CSA shrinkage was autogenous due to very low w/c.
Another concrete video - true to form. But, but how does the cost compare and how will the cost trend?
Great question!
In my experience the cost is similar between OPC and PLC but you need to check locally.
have you ever check the radioactivity of the concrete made with fly ash?
You make a great case with your extensive knowledge of all things concrete for these formulations. The merits of PLCs can and do stand on their merits as to performance and cost savings. It is, though, sad and disappointing to see how you have capitulated to the siren song of the "CO2 emissions are bad" crowd. I sincerely and respectfully ask you to properly investigate the truth of CO2 in our atmosphere.
how does plc affect plasticizers?
Professor Ley, what would be the w/binder ratio for durable PLC work? Remains 0.35-0.45 as suggested for normal Portland cement? Can we use water reducing admixture as normal and how about the influence of SBR polymeric admixture to the hydration process of PLC?
What is the specific gravity of Type IL (or other PLC)? It should be less than 3.15, and what constituent is increased to compensate for the lower SG? Sand? Or do you keep the SG of the PLC at 3.15 so that the mixtures are comparable as the powder contents are the same?
Very good video. What is the effect of the ice melt used on New England highways?
I don't think there are any concerns. Deicer salts can sometimes attack the calcium hydroxide in the concrete. A PLC should have less calcium hydroxide and so should perform better.
Where can we see the cited sources? Is there update on these? REALLY want to make the case to have suppliers know these options, and ask then to use lower CO2 mix.
I'm planning on making concrete weight lifting plates (450mm diameter) for training at home in quarantine. How would I place the rebar to prevent cracks since I'm going to be lifting and dropping the weights on the circular edge (probably onto some rubber matts to decrease impact shock). Is using 4 pieces of rebar in a Hash pattern enough?
hello doctor Tyler
could you kindly write the whole citation of the reference you gave on minute 2:26 (Matschei et al., 2008)
i couldn't find the graph nor the paper. I need it for my research
Professor Ley, my request, make a full video lecture about footing design????
Thanks for the comment. What do you want to know?
@@TylerLey in our campus our professor did'nt cover our reinforced concrete design course due to covid-19 thats why I am requesting you to...
So that we learn from your channel in home
@@TylerLey wall footing and eccentrically loaded column footing as per ACI recommendations...
50% portland reduction is no joke. I assume that your building has plc painted surfaces. Any differences with paint or other coatings as far as adhesion? Great video!
Thanks! We don't have any adhesion problems. The PLC performs just like typical portland cement in my experience.
Agree with Tyler, I couldn't taste any difference between PLC and portland...
Your telling me they didn’t even investigate what happens when they add 3% lime stone only.
I notice you referenced Compressive Strength, but...I've seen a clear reduction is Flexural Strength (breaking beams). The aggregate (crushed limestone) seems to not bond with the cement, much like you would expect if one had used an unwashed limestone. Trying to figure out why the flexural strength is lacking...anyone have any ideas?
What is the percentage of #200 sieve washout in the aggregate after conducting a gradation test? In my experience, the dust in the rock can lead to bonding issues. Additionally, I suspect that the additional limestone may contribute extra dust without providing any beneficial bonding component in the concrete. Concrete can be stronger in compaction and weaker in tension… this could cause worse tension breaks.
**One concept i have been wondering about (and what may make a good video or two), is can non-coal/petrolium coke methods be used for producing some of the materials you mentioned in this video and other (Mainly Fly Ash, Fumed Silica, Slag (Not sure if "Clinkers" are different, but those too) ) **
The main methods are via Biomass and/or Refuse Derived Fuel (or RDF) Plants
Many Operate in Similar Methods (or even "Co-Fire" coal (but i hate coal so don't condone the practice, but this is besides the point) ) to Conventional Coal Plants. In some areas they are catching on, especially Europe where landfills are almost non-existent due to policy differences compared to the USA.
I wonder with there may be chemical diferences that may make it not work or work differently (as you pointed out with the need for chemical analysis of feedstocks in one video for this exact reason) ?
Also Cement / Lime Kilns Could Potentially Run Off of Charcoal (Or Bio-Petrochemical Coke)
(I'm a nerd on this, but not an expert, so could help with research/video stuff if need be)
How about high strength concrete? 70mpa?
What do you think about LC3 ?
I think it has promise if you don't need high strengths and you are in a mild environment. You also need an abundance of clay that is close by. I think there are lots of barriers in the US but it may work in other countries.
Do we have any examples or insights about longevity? Is there any positive or negative effect on tensile strength, shear strength, spalling, etc?
There are projects that have been in place for decades with PLC. I think the performance is very comparable to typical cement.
@@TylerLey Thanks! It seems like a win-win!
Sir plssss help me ,I want to do a project on beam but I have no idea or please suggest me a project topic am doing my final year ME structure
Tyler, I want to reach out to you for some guidance on a project as I value, trust your input, how can I do that ?
Is it cheaper than regular cement?
The cost is similar in my region.
How much co2 is created to produce limestone and gypsum?
Not very much. There is some for the energy to crush them.
@@TylerLey Sorry but I had to ask, seems not enough people today ask if the solution to a problem is just as bad or worse than the problem itself. Love your videos by the way!
Why aren't there many songs about concrete:
About how to cure and dry?
Concrete is a composite, but only reinforced
If there is rebar on the inside
.
So we've been told, and some choose to believe it
I know they're right, wait and see
Someday we'll find it, the concrete connection
The Builders, the designers, and me.
When you say "carbon footprint" I wonder if you realize you repeating a marketing campaign that BP came up with in the 90's?
Isn't this just "greenwashing" since substituting portland for limestone is just eliminating the work and cost of converting that limestone to portland?
first view wohooo
Thank you for being #1!
So many carbon narrative alternatives end badly if you pull the string. For example limestone is cheap, natural gas for kilns is not - why hasn't Limestone been used before? What was wrong with a cheap material back before the climate narrative replaced free market thinking? I think I'm convinced that you CAN add limestone, but I'm not sold on the idea that I SHOULD add limestone.
I'm a huge fan, I'm a Freak 👍❤🧱
Thank you for all the comments!!!!