I am building an addition on the side of my home. When we poured the one section of wall 8″ thick we ran out of concrete in the truck at the end of the day. 3 days later I poured the rest of it. Basically we top the wall off . The vertical rebar did come up high enough so that the “topping off “and the lower 1st pour where tied together.
There was a spot where we only topped off 6″ on a 5′ run.
I have two questions
1. Should I be worried about this five foot runs comprehensive strength seeing how its only 6″ thick on the top of the wall?
2. Should I be treating this seam any differently on the out side aside from the tarring?
Replies
I guess you realize now, you should have gotten the plant to send a balance.
Your cold joint should be made watertight, by parging (stucco)on the outside or asphalt foundation coating.
If you left the top of the wall rough, it should key OK by what's called "aggregate interlock". At least as strong as masonry block.
If you left the top of the wall rough, it should key OK by what's called "aggregate interlock". At least as strong as masonry block.
Meaning as strong as a mortar joint (which is very weak)? or as strong a CMU?
Yep.
But the dowels that Alltrade drilled and grouted should improve things.
Compression wise, it's as strong as concrete.
Lateral movement wise, it's as strong as the foundation wall to footing connection. That is the keyway effect, or interlock, Eric was talking about.
Tension wise, it's stronger than the rebar. Not much stronger, but an appreciable bit.
Water tightness is a little compromised at the cold joint. Parging will fix that and make it look better too.SamT
Anyone who doesn't take truth seriously in small matters cannot be trusted in large ones either. [Einstein] Tks, BossHogg.
Compression wise, it's as strong as concrete.
Lateral movement wise, it's as strong as the foundation wall to footing connection. That is the keyway effect, or interlock, Eric was talking about.
Tension wise, it's stronger than the rebar. Not much stronger, but an appreciable bit.
Are you referring to the mortar joint? If so, that seems different than what CivEs are taught.
Basically, the purpose of mortar is to level the block. It adds little strenth to the wall. Reinforcing in the mortar helps, but not much. Grouting the block helps more.
Compressional strength is decent, but that doesn't really help much.
If you do a little searching on "surface bonded block", you will find some interesting studies and articles comparing mortared block (quite weak) and surface bonded block (surprisingly strong). The difference in strength surprised me - I won't do a mortared block wall again.
I think you're in the wrong thread.
From:
AllTrade <!----><!---->
6:45 am
To:
ALL <!----><!---->
(1 of 8)
87683.1
I am building an addition on the side of my home. When we poured the one section of wall 8" thick we ran out of concrete SamT
Anyone who doesn't take truth seriously in small matters cannot be trusted in large ones either. [Einstein] Tks, BossHogg.
I think you're in the wrong thread.
No, this is the right thread. I was responding a prior comment implying that mortar was as strong as a CMU.
Oh.
Sorry.
I thought you were replying to me.SamT
Anyone who doesn't take truth seriously in small matters cannot be trusted in large ones either. [Einstein] Tks, BossHogg.
I thought you were replying to me.
I was - I was replying to your comments on the compressional strength of mortar.
I still think you are in the wrong thread, simply because you are the only one here, other than a one time comparison to the compressive strength of masonry block by ericicf, who is talking about mortar, mortar joints, and CMUs.
The rest of us were talking about a cold joint in a poured wall.
You can blame me for the confusion if you prefer, since I made the mistake of not readdressing my reply to AllTrade instead of leaving the address at its' default setting of the post I clicked the Reply button in, which happened to be the last post in the list at that time.SamT
Anyone who doesn't take truth seriously in small matters cannot be trusted in large ones either. [Einstein] Tks, BossHogg.
The top of the wall is rough and I drilled some 1/2" holes and spiked in some more rebar pins to tie them together.
Thanks to you all for making me feel better. I usually sub out this work to my Mason but this was my home and I had plaenty of wood for the forms and was willing to give it a shot. My math screwed me on the short delevary and I just wanted to make sure it was ok. I will address the parging of the crack. I will run my grinder blade in a tic tac toe pattern across the seam first. The area is just below the slab hieght so looks are no concern because it will be below grade by a few inchs. Above grade I will leave alone/ no parging.