Many thanks for this video. Am looking to make cement hollow blocks, and have been advised to use minus 1/4" gravel, washed concrete sand, cement and water on a ration of 4 gravel, 3 sand, 2 cement and 1 water. All measurements to be done with dried materials, by weight, not volume. The locals work on a 15 MPa mix strength, but, suspect that mine is going to be a tad stronger.
Thanks for the vid. Came here from your website which has been useful for me on a lot of DIY jobs. I'm in Japan and here the 1:2:3 mix is the one true mix as far as I can tell - but in Japan there's only ever one true way of doing anything... 🤣 Anyway, the thing that gets me is the metric MPa ratings vs PSI ratings just don't seem to match up. Going the standard 1:2:4 mix is rated 2500psi, but only 15MPa, which is 2175psi. 1:2:2 is rated at 4500psi but only M20 (which is 2900psi). M25 or 25MPa concrete at 1:1:2 (what I just poured for my deck piers because why not over-engineer them 😎) translates to 3625psi, but it's not even on the US table. Obviously in the real world a 1:2:4 or 1:1:2 mix or whatever is what it is and doesn't care about national borders or man made measuring systems. I'm just wondering are US engineers over-estimating the strength of their concrete, or are Europeans under-estimating theirs?
Thanks, need to build a 18(w)x38(L) garage pad and contractors are quoting 4000psi, so this is good to know! I built forms for concrete and set them up, but never handled the pours, that was another crews job, so I know nothing lol
My soil is clay. My regional temperature can get as hot as 100 degree in the summer and as cold as 14 degree in the winter. But these temperatures are rare. It mostly hover around 30 degree to 80 degree year round. With these conditions, I propose my house-front sidewalk to be 4,000 PSI concrete, fiberglass rebar, 6 inch thick.
But here in Colombia a forman told me to make strong concrete to use 3 buckets of material for 1 cemento. How is it that you say 3 buckets of sand and 3 crushed rock total of 6 buckets can make 3k psi concrete.
Thank you so very much for the video, I've been looking for one and yours is the only one answered my questions. I'm trying to build a wood fire oven and since I've got zero experience in anything related to building and construction, I didn't know but few facts like the thickness of the slab which is recommended to be 120mm and 40 mpa, the latter was so vague - I'm not sure if 40mpa is the right mixing ratio, sounds too much for a 120cm width x 180cm length x 12cm depth, would very much appreciate your advice please. Sorry for my lengthy comment and many thanks again
Are these ratios by weight or volume? You said “shovels full”, so I assume by volume. Would unpacked flush bucket loads be more accurate, or does it need to be that precise?
What is your cost difference between 3k and 4k psi concrete? Is it a linear ratio, as 33% more dollars?...........I watch, like, and save all your great videos!
You always want various sizes of gravel or river rock so the rocks can lock together better. If you have only 1 size of rock the gaps will be large and the rocks will be lose
White portland cement is just something you can buy. To my understanding, the color in cement comes from a bunch of oxides that aren't actually needed and aren't found in all cement, so you can just buy a "white grade" cement. Sand comes in white. Just buy white sand, which is already on the market for other reasons. If you are pouring a small amount, you might look to specialty sources for aggregate. I have seen people pouring countertops with aquarium rocks, though that is a very fine aggregate. Depends on what you intend to do with it. But depending on application, you may not WANT white aggregate. A lot of terrazos seem to be based on a colored aggregate inset into a white base mix. Really though, I would think this is the primary reason to mix your own, in addition to say, mixing large amounts in remote locations, like say, you need to pour a far off grid foundation but want to save some money over buying premixed bags. I would be careful on the aggregate though. I have seen some examples of people using relatively fragile stone for testing, and it has broken relatively easily. I am no geologist, but make sure whatever white aggregate you choose doesn't end up being chalk or anything. Choose your aggregate carefully for your application.
1995 called, they want their website back. Just kidding, looks like you got a new one now. Thank you for making the only helpful mixing video.
Exactly the video I was looking for. The detailed breakdown is brilliant.
Very clearly broken down, great video! Am going to diy a pad for the hottub, and wanted to make sure it was strong. Thanks!
Glad it was helpful!
GREAT CLASS OF HOW TO MIX CONCRETE AND GET THE BEST, THANKS
Great video ,really well explained . You've answered all the questions I had , thanks.
Very informative, thanks a lot for sharing this.
You're welcome!
If you make a booklet or something with all this info and more I would definitely buy it
Many thanks for this video. Am looking to make cement hollow blocks, and have been advised to use minus 1/4" gravel, washed concrete sand, cement and water on a ration of 4 gravel, 3 sand, 2 cement and 1 water. All measurements to be done with dried materials, by weight, not volume. The locals work on a 15 MPa mix strength, but, suspect that mine is going to be a tad stronger.
Thank you for this video! Couldn't ask for better clarification 👍
Thanks for the vid. Came here from your website which has been useful for me on a lot of DIY jobs.
I'm in Japan and here the 1:2:3 mix is the one true mix as far as I can tell - but in Japan there's only ever one true way of doing anything... 🤣
Anyway, the thing that gets me is the metric MPa ratings vs PSI ratings just don't seem to match up. Going the standard 1:2:4 mix is rated 2500psi, but only 15MPa, which is 2175psi. 1:2:2 is rated at 4500psi but only M20 (which is 2900psi). M25 or 25MPa concrete at 1:1:2 (what I just poured for my deck piers because why not over-engineer them 😎) translates to 3625psi, but it's not even on the US table.
Obviously in the real world a 1:2:4 or 1:1:2 mix or whatever is what it is and doesn't care about national borders or man made measuring systems. I'm just wondering are US engineers over-estimating the strength of their concrete, or are Europeans under-estimating theirs?
I was wondering that too. Maybe the cement has different characteristics, or maybe the strength is measured with a different method.
Thanks, need to build a 18(w)x38(L) garage pad and contractors are quoting 4000psi, so this is good to know! I built forms for concrete and set them up, but never handled the pours, that was another crews job, so I know nothing lol
Thank you so much for this!!!
I loved this information. Thank you
My soil is clay. My regional temperature can get as hot as 100 degree in the summer and as cold as 14 degree in the winter. But these temperatures are rare. It mostly hover around 30 degree to 80 degree year round. With these conditions, I propose my house-front sidewalk to be 4,000 PSI concrete, fiberglass rebar, 6 inch thick.
So my question is ,in today's market is it cheaper to buy the stuff and do it yourself ,or hire it out
mate, you are the best
But here in Colombia a forman told me to make strong concrete to use 3 buckets of material for 1 cemento. How is it that you say 3 buckets of sand and 3 crushed rock total of 6 buckets can make 3k psi concrete.
Hi Mike, thank you for sharing. Your video was very informative specifically for a begginer like me.
Love your videos
Thank you so very much for the video, I've been looking for one and yours is the only one answered my questions.
I'm trying to build a wood fire oven and since I've got zero experience in anything related to building and construction, I didn't know but few facts like the thickness of the slab which is recommended to be 120mm and 40 mpa, the latter was so vague - I'm not sure if 40mpa is the right mixing ratio, sounds too much for a 120cm width x 180cm length x 12cm depth, would very much appreciate your advice please. Sorry for my lengthy comment and many thanks again
Are these ratios by weight or volume? You said “shovels full”, so I assume by volume. Would unpacked flush bucket loads be more accurate, or does it need to be that precise?
I don't see the weight of gallons of water to any of the mixes.
Do not forget the ratio of cement to water which is very important. Water should never exceed 50 percent of the cement.
What about plasticizer. It's mentioned many of you videos that a plasticizer is used. Who determines how much and what kind of plasticizer is used.
Good job
What is your cost difference between 3k and 4k psi concrete? Is it a linear ratio, as 33% more dollars?...........I watch, like, and save all your great videos!
Can you give me the numbers for how to make 5 yards of 5000psi mix
1cement : 1sand : 3stone
If you skip the stone and use just sand and cement how does it affect strength?
Do 4000 is used for all exterior stuff but footers and foundations can be 3500? Why’s that?
Do you have a video for a foundation footer? thank you
If you add something like Ames Superprimer along with the water, does it increase strength substantially?
How could I measure the PSI in my driveway, if feasibly possible?
Is this based from ACI Standard?
Thank you
Do a video on how to calculate measuresments if the sand is wet
I'll see if I can make that happen!
Just get the moister levels of your sand.
Hello. Any reason to choose different size aggregates in your mix? Noticed some had 3/8, some 3/4 and some both.
You always want various sizes of gravel or river rock so the rocks can lock together better. If you have only 1 size of rock the gaps will be large and the rocks will be lose
How do I get a very white colored concrete? I don’t want to color it.
White portland cement is just something you can buy. To my understanding, the color in cement comes from a bunch of oxides that aren't actually needed and aren't found in all cement, so you can just buy a "white grade" cement. Sand comes in white. Just buy white sand, which is already on the market for other reasons.
If you are pouring a small amount, you might look to specialty sources for aggregate. I have seen people pouring countertops with aquarium rocks, though that is a very fine aggregate. Depends on what you intend to do with it. But depending on application, you may not WANT white aggregate. A lot of terrazos seem to be based on a colored aggregate inset into a white base mix.
Really though, I would think this is the primary reason to mix your own, in addition to say, mixing large amounts in remote locations, like say, you need to pour a far off grid foundation but want to save some money over buying premixed bags.
I would be careful on the aggregate though. I have seen some examples of people using relatively fragile stone for testing, and it has broken relatively easily. I am no geologist, but make sure whatever white aggregate you choose doesn't end up being chalk or anything. Choose your aggregate carefully for your application.
👍