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Need to make a cast in place lintel over a 9′ wide opening. Engineer specified 4 – #5 pieces of rod and 3000 psi concrete. The lintel’s dimensions will be 8″x8″x ~11′ and will have vertical rod tying into the masonry walls on either side of the opening. It will not be supporting that much – a bond beam above (‘U’ block with rod, site poured), a 2×8 PT sill above that that will be anchor bolted into the bond beam, and then a gable end truss nailed onto the PT sill.
OK, so I got it all formed up, rod tied in and I’m ready to pour. Didn’t want to get a concrete truck as it is only about 5 cu ft of mix to be poured. I’ve got Portland cement, masons sand, and ½” aggregate (washed bluestone) on site. So what should be the mix? (Cement/Sand/Gravel) I could come up with something myself, but as long as I got a couple of days (waiting for warmer temps) I thought I’d throw it out there to you guys. Also, is the mason’s sand OK?
TIA
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ask johnnie brown .. or gabe..
.. i don't know the mix ratiio.. i just order from the ready mix
my old mortar man days .. it was 2/3/5 for about a 1500 # mix.. but i wouldn't swear by that....
also... the water amount has a huge effect on the ultimate strength too..
b but hey, whadda i no ?
*Matt: A couple of thoughts. If you have a good relationship with a redi-mix supplier you might be able to go to the plant with a couple of wheel borrows and have them fill the borrows in the back of your pick-up. You can take the concrete to your site and use it. We do this with similar amounts all the time. We have only river gravel or crushed rock in our area. I am not familiar with your 1/2" stone. I grew up feeding a 1 sack mixer with a gravel scoop. We used a ratio of 5 gravel to 1 cement. This is very close to a 6 sack mix. Assuming you will mix this by hand the uniformity is not as good as with a mixer truck. I would probably be inclined to use a 4 or 4.5 to one mix for what you are doing. If you use more sand use a little more cement. Aggregate with a high ratio of fines requires more cement to reach required strengths. If you know any concrete people in your area they should be able to tell you an exact ratio using the material you have. Ron
*Ron:I do have an electric mixer. I hate mixing anything by hand because it is i way too much like work, and the results are questionable. If you don't mind, please repeat your recomdation for the ratio gravel/sand/cement. Whatever I do come up with, I'll go a little rich on the cement for extra strength.Thanks
*Thanks to those who replied. I'm going to go do the job today, and am going to go with a 1-2-2 mix. Maybe next time I'll try talking my local Ready-Mix into giving (selling) me 1 or 2 wheelbarrows. God knows I've spent a lot of money with them.
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Need to make a cast in place lintel over a 9' wide opening. Engineer specified 4 - #5 pieces of rod and 3000 psi concrete. The lintel's dimensions will be 8"x8"x ~11' and will have vertical rod tying into the masonry walls on either side of the opening. It will not be supporting that much - a bond beam above ('U' block with rod, site poured), a 2x8 PT sill above that that will be anchor bolted into the bond beam, and then a gable end truss nailed onto the PT sill.
OK, so I got it all formed up, rod tied in and I'm ready to pour. Didn't want to get a concrete truck as it is only about 5 cu ft of mix to be poured. I've got Portland cement, masons sand, and ½" aggregate (washed bluestone) on site. So what should be the mix? (Cement/Sand/Gravel) I could come up with something myself, but as long as I got a couple of days (waiting for warmer temps) I thought I'd throw it out there to you guys. Also, is the mason's sand OK?
TIA