Cement ties
Moderator: Harold_V
Re: Cement ties
Seems strange that concrete ties hold up. Concrete is not known for its tensile strength, and the ties certainly are relatively slender. I'd expect them to crack easily. Not so?
H
H
Wise people talk because they have something to say. Fools talk because they have to say something.
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Re: Cement ties
Hi Harold, some of the previous comments on the serivicebility of concrete ties were right on the mark, one of our club members works for Metro North and advised me of the the issues they had with concrete ties, and to the extent that I'm able, I'll try not to make those same mistakes. It must be my Roman roots, I love working with concrete; the first 21 years of my career was in heaven highway and bridge construction, so this is a little trip down memory lane. My ties are for the most part pretty small, 9" long 3" deep with a trapezoidal cross section average width 2-1/4"; they're about the size of a brick so they shouldn't develop too much in the way of bending stress, chipping, impacts, freeze thaw and thermal expansion are my biggest concerns. I do reinforce them with a loop of 14 ga. tie wire around the two plastic blocks 1/4" down from the top to resist some of the thermal stress from the expansion of the plastic blocks and to strengthen the edge distance around the blocks, I also add a longitudinal 9ga. wire about a half inch from the bottom for crack control, and I cure them for 7 days under water to really harden them up. Who knows if these things are going to hold up, it's all an experiment, we may learn what not to do....and if they do work, who's going to make thousands of them to replace the existing ties? When that subject comes up, everybody walks away. Regardless, it's fun for me and who knows what the future may bring.
Re: Cement ties
Thanks. It's obvious you've put your heart and soul in the tie project. I'm really impressed with the underwater cure.
I'll continue following this thread with interest.
I built an adjustable form and cast multiple dyed concrete window sills with a drip lip for our house. I used three lengths of #4 rebar for reinforcement. One hell of a lot of work, but they turned out really nicely and go well with the synthetic stucco (dryvit) finish applied to the house.
H
I'll continue following this thread with interest.
I built an adjustable form and cast multiple dyed concrete window sills with a drip lip for our house. I used three lengths of #4 rebar for reinforcement. One hell of a lot of work, but they turned out really nicely and go well with the synthetic stucco (dryvit) finish applied to the house.
H
Wise people talk because they have something to say. Fools talk because they have to say something.
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Re: Cement ties
We installed the batch of concrete ties with the embedded plastic blocks, they went in easily with the tie plates and look great. I'm going to make one more batch of ties before winter, and those will be made with fiber reinforced concrete for a little extra reinforcing. As I said before, my biggest concern is the freeze/thaw cycles. I put one of the ties with the embedded plastic blocks in the freezer to see how much of a space opened between the concrete and plastic. Even though the coefficient of expansion for the plastic lumber is 6 times that of concrete, after two days in the freezer the opening was very narrow, but more than enough to allow water to enter and freeze. So upon learning that Sakrete makes a fiber reinforced mix, I figured that I'd give it a try and see if there is a difference in performance between the regular concrete and fiber reinforced mix. I'll post the results.
Re: Cement ties
The fiber makes the concrete much tougher I'd highly recommend it. I just used it on my foundation pour, and even the smallest places where the concrete seeped into gaps in the form and protruded outwards, they were surprisingly difficult to chip off.
I would be concerned that the expansion rate difference between the plastic and concrete will cause problems as they "cycle".
I would be concerned that the expansion rate difference between the plastic and concrete will cause problems as they "cycle".
Re: Cement ties
Yep! If water enters and freezes, each iteration will widen the gap until the 'crete fails.
Water is a huge force when cycled through hot and cold.
H
Wise people talk because they have something to say. Fools talk because they have to say something.
Re: Cement ties
RK...not sure I would agree with that. Perhaps it's based MORE on the application. Maybe a foundation is an acceptable use...but a driveway flat surface...NOT! My house was built in the mid 90's. The driveway had the shredded plastic mixed in. The shredded plastic was more experimental back then. Within a year, the top surface was chipping and spalling. Understand the use of shredded plastic has been stopped.rkcarguy wrote: ↑Mon Sep 20, 2021 4:18 pm The fiber makes the concrete much tougher I'd highly recommend it. I just used it on my foundation pour, and even the smallest places where the concrete seeped into gaps in the form and protruded outwards, they were surprisingly difficult to chip off.
I would be concerned that the expansion rate difference between the plastic and concrete will cause problems as they "cycle".
The following year, got the contractor back. His first comment...Oh, that's from the Winter road salt. My response...My cars drip on the garage floor and that surface isn't failing. With every reason (read excuse) he could come up with...I was able to shoot him down. He offered to replace the driveway...IF...I paid for the concrete. Shoot, my driveway is 1500 sq. ft. for a side entrance garage...as much area as a small house. Didn't have that kind of money laying around then so I just let it got. While I'm sure there are reputable contractors out there...more than willing to work with them...but don't need all their lines or excuses. So, when it comes to shredded plastic reinforced concrete...buyer beware. Carl B.
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I don't walk on water...I just learned where some of the stepping stones are!
I love mankind...it's some of the people I can't stand!
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Re: Cement ties
Fiber reinforcement is quite different from shredded plastic.
Re: Cement ties
Plastic isn't a good reinforcement, I understand that. The stuff that was used for mine was more like fiberglass strands, and they also offer one that is like metal slivers which I didn't go for. Most builders of foundations and shop floors around here use it in lieu of rebar, I used rebar anyway and then went for the fiber as well because it only adds about $120 to the cost of the concrete. Not sure I'd use it on a driveway, though.
Short story, there is lots of different fiber out there, do a little research and try a good one.
Short story, there is lots of different fiber out there, do a little research and try a good one.
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Re: Cement ties
The promised follow up on how well the concrete ties held up after two winters in service is that they performed well.
Re: Cement ties
John, is your next step going to be trying pandrol clips?
Keith
Keith
Re: Cement ties
Amazing! Thanks for the update.
H
H
Wise people talk because they have something to say. Fools talk because they have to say something.