You are really awesome Mr Ley you have made me in love with concrete Lol. Actually,I didnt get what is the benefit of air except economic and workable!!and how do we measure the air ratio?!and my second question is,does cement act to give the concrete strength or only we use it to adhesion?
If I order concrete with a certain water cement ratio, say .4, and minimum 5kpsi, how do I know for sure the concrete company delivers exactly what was ordered and they didn’t cut corners?
Typically, you would order concrete by its 28 day strength (35Mpa cylinder sttrength at 28 days). To check if you get what you ordered, you usually make cylinder samples in accordance with ASTM C31 and test the 28 day strength in accordance with ASTM C39.
dear sir, while studying the Abrams law in a text book, i came across a statement that says " """"According to the water cement law, the strength of concrete only depends upon the quantity of water used in workable concrete mix and is quite independent of the proportion of cement and aggregate"""""". i cant visualize how the strength is independent of proportion of cement and aggregate ?
Good question! I am going to cover this exact topic in a future video. It is not as easy as the text book says. However, the water to cement ratio is really a measure of how spaced the cement particles are within the paste. If the particles are close together (low w/cm) then it will be easier for the hydration products to grow together. If the particles are far apart (high w/cm) then it will be harder for them to grow together. This behavior does not depend how much cement is in the mixture. This means that the strength of the mixture should be only dependant on the w/cm. This concept works great in the typical mixtures but doesn't always work in very low w/cm, high strength concrete, or if you have weak aggregates or weak bond between the aggregates and the paste. More details to come!
I cant understand why I NEVER HEARD THE BASICS! iN ONE OF YOUR VIDS you seemed to be worried about water left in a mixer even!you even said once its mixed there is no way to know water content after its mixed...WHAT ABOUT A SLUMP TEST?aND THE STANDARDS ARE THAT WE USE A 4 INCH SLUMP VERY COMMON! I DONT KNOW WHY SLUMP AND THE WORD VIBRATOR ARE NOT ADDRESSED HERE,just looking at the title of this vid.An on- the job engineer told me we had to pour a 4'' slump,but if we wanted to add water to make it easier to work and get beter consolidation.noHONEY COMB,WE COULDadd half a sack to a yard..of course,not on that job,just in general. aLL THIS IS much too complicated..basically too much water makes it weak...be sure to vibrate but be careful not to over do it..dont be tight and try to save 6 bux per yard,cutting PORTLAND content...6sack mix makes 4500lb.concrete..i think that number iscorrect..but I cant say I learned thoseimportant numbers here!
Thanks for the comment. Not all videos cover all topics. The slump test was invented in 1911. It was an awesome tool at the time but now it doesn't mean much. We have a ton of different ways to modify our slump from admixtures, to supplementary cementitious materials, to aggregate gradations. Slump is only a measure of consistency. There are new ways coming to measure the water to cement ratio and so stay tuned. I am sorry that whoever you are working with is trying to be so narrow in how they will accept concrete. I don't believe in this approach and I think performance is much more important. However, this will take education, patience, and time to teach people how to do things differently. Here are a few videos that might be helpful: Intro to concrete mixture design - ruclips.net/video/rv-JwoRfV0E/видео.html performance based specifications - ruclips.net/video/U6TTgW2oLqM/видео.html
This is an excellent video.
Thanks Tom!
Nice & Informative Lecture Sir
🙏 Thanks.
You are really awesome Mr Ley you have made me in love with concrete Lol.
Actually,I didnt get what is the benefit of air except economic and workable!!and how do we measure the air ratio?!and my second question is,does cement act to give the concrete strength or only we use it to adhesion?
Sir , can you make some videos on high strength concrete and the most important things to be kept in mind while designing HSC .
Dear Tyler really apreciate your videos if i get the required strength at the 7th day can i stop the water curing?
What is the best component that defines the compressive strength of a concrete?
A. Cement
B. Water
C. Gravel
D. Sand
If I order concrete with a certain water cement ratio, say .4, and minimum 5kpsi, how do I know for sure the concrete company delivers exactly what was ordered and they didn’t cut corners?
Typically, you would order concrete by its 28 day strength (35Mpa cylinder sttrength at 28 days). To check if you get what you ordered, you usually make cylinder samples in accordance with ASTM C31 and test the 28 day strength in accordance with ASTM C39.
dear sir, while studying the Abrams law in a text book, i came across a statement that says " """"According to the water cement law, the strength of concrete only depends upon the quantity of water used in workable concrete mix and is quite independent of the proportion of cement and aggregate"""""". i cant visualize how the strength is independent of proportion of cement and aggregate ?
Good question! I am going to cover this exact topic in a future video.
It is not as easy as the text book says. However, the water to cement ratio is really a measure of how spaced the cement particles are within the paste. If the particles are close together (low w/cm) then it will be easier for the hydration products to grow together. If the particles are far apart (high w/cm) then it will be harder for them to grow together. This behavior does not depend how much cement is in the mixture. This means that the strength of the mixture should be only dependant on the w/cm.
This concept works great in the typical mixtures but doesn't always work in very low w/cm, high strength concrete, or if you have weak aggregates or weak bond between the aggregates and the paste. More details to come!
Tyler Ley thankyou sir for your reply. i am eagerly waiting for the video.
Amrit,
You can find the video here: ruclips.net/video/K_0sn5KlOvQ/видео.html
What do you say at 6:09? Air is really important for "free solderability"?… I listened several times and still can't get it!
I'm fairly sure that he says " ... freeze/thaw durability." Hope that this helps. 😊
I cant understand why I NEVER HEARD THE BASICS! iN ONE OF YOUR VIDS you seemed to be worried about water left in a mixer even!you even said once its mixed there is no way to know water content after its mixed...WHAT ABOUT A SLUMP TEST?aND THE STANDARDS ARE THAT WE USE A 4 INCH SLUMP VERY COMMON! I DONT KNOW WHY SLUMP AND THE WORD VIBRATOR ARE NOT ADDRESSED HERE,just looking at the title of this vid.An on- the job engineer told me we had to pour a 4'' slump,but if we wanted to add water to make it easier to work and get beter consolidation.noHONEY COMB,WE COULDadd half a sack to a yard..of course,not on that job,just in general. aLL THIS IS much too complicated..basically too much water makes it weak...be sure to vibrate but be careful not to over do it..dont be tight and try to save 6 bux per yard,cutting PORTLAND content...6sack mix makes 4500lb.concrete..i think that number iscorrect..but I cant say I learned thoseimportant numbers here!
Thanks for the comment. Not all videos cover all topics.
The slump test was invented in 1911. It was an awesome tool at the time but now it doesn't mean much. We have a ton of different ways to modify our slump from admixtures, to supplementary cementitious materials, to aggregate gradations. Slump is only a measure of consistency. There are new ways coming to measure the water to cement ratio and so stay tuned.
I am sorry that whoever you are working with is trying to be so narrow in how they will accept concrete. I don't believe in this approach and I think performance is much more important. However, this will take education, patience, and time to teach people how to do things differently.
Here are a few videos that might be helpful:
Intro to concrete mixture design - ruclips.net/video/rv-JwoRfV0E/видео.html
performance based specifications - ruclips.net/video/U6TTgW2oLqM/видео.html