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Why coated rebar is still a problem
- Thread starter StevieC
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I ran over a bit of 1 inch rebar sticking out of the ground, straight through the sidewall of my tyre. I was not impressed - if it had been coated I would've seen it and avoided the cost of a new tyre.
Yeah we have a piece of it sticking our of the driveway concrete transition strip at my office and I keep going out the other side to miss it.
It has been reported to the landlord but I'm sure they will wait until something happens before fixing it.
Hard to see but it's sticking up more now since this photo was taken by Google Street View in August.
It has been reported to the landlord but I'm sure they will wait until something happens before fixing it.
Hard to see but it's sticking up more now since this photo was taken by Google Street View in August.
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Originally Posted by StevieC
There is quite a few that think otherwise. I got PM's to prove it. But we'll leave that discussion for PM only.
I think this thread is done unless anyone else has anything to add to the Rebar discussion.
Ohhh, the dreaded PM "list"...there used to be a troll blog for the mechanically illiterate out there somewhere, where they would sit around, and circle...well you know what...about how mean and nasty certain posters are.
Not sure if it's still extant, but you could ask your mechanically illiterate pals via PM is it's still there.
Now, please counter my position with something factual...youtube is a worse reference than wiki. The PM's PROVE that I don't know engineering ?
Would be easy as pie to wheel out the real facts, rather than whisper secrets in each other's ears
Another thought to ponder on the topic...are battleships made of stainless steel, or hot dip galvanised ?
There is quite a few that think otherwise. I got PM's to prove it. But we'll leave that discussion for PM only.
I think this thread is done unless anyone else has anything to add to the Rebar discussion.
Ohhh, the dreaded PM "list"...there used to be a troll blog for the mechanically illiterate out there somewhere, where they would sit around, and circle...well you know what...about how mean and nasty certain posters are.
Not sure if it's still extant, but you could ask your mechanically illiterate pals via PM is it's still there.
Now, please counter my position with something factual...youtube is a worse reference than wiki. The PM's PROVE that I don't know engineering ?
Would be easy as pie to wheel out the real facts, rather than whisper secrets in each other's ears
Another thought to ponder on the topic...are battleships made of stainless steel, or hot dip galvanised ?
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RE design and manufacture...thin cover is one of the worst things that you can do with Concrete...the chemicals have to migrate through the outer concrete towards the rebar. Improperly installed reinforcing with low cover means that the chemicals will reach the rebar quicker, and cause rust...rust takes up twice the space of steel, and so "pops" the outer layer of concrete off, a process known as spalling...all those little pock marks up high rise buildings are spalls caused by corrosion...predominantly carbonation
Impressed current is one of my fave corrosion prevention techniques, although rarely applied (I had it on a steel ash water tank, 40 years old, zero corrosion in a sulfuric acid environment ph sometimes hitting 4).
https://metallisation.com/applications/cathodic-protection-of-steel-in-concrete/
Impressed current is one of my fave corrosion prevention techniques, although rarely applied (I had it on a steel ash water tank, 40 years old, zero corrosion in a sulfuric acid environment ph sometimes hitting 4).
https://metallisation.com/applications/cathodic-protection-of-steel-in-concrete/
From an Engineering Journal
Another link from another source: https://www.sciencedirect.com/topics/engineering/rebar-corrosion
And another: https://www.cement.org/learn/concrete-technology/durability/corrosion-of-embedded-materials
As for the PM's it's your attitude and unwillingness to discuss things without beating someone down in the manner you reply.
Not my words. Words of others.
Another link from another source: https://www.sciencedirect.com/topics/engineering/rebar-corrosion
And another: https://www.cement.org/learn/concrete-technology/durability/corrosion-of-embedded-materials
As for the PM's it's your attitude and unwillingness to discuss things without beating someone down in the manner you reply.
Not my words. Words of others.
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Originally Posted by Shannow
Originally Posted by StevieC
There is quite a few that think otherwise. I got PM's to prove it. But we'll leave that discussion for PM only.
I think this thread is done unless anyone else has anything to add to the Rebar discussion.
Ohhh, the dreaded PM "list"...there used to be a troll blog for the mechanically illiterate out there somewhere, where they would sit around, and circle...well you know what...about how mean and nasty certain posters are.
Not sure if it's still extant, but you could ask your mechanically illiterate pals via PM is it's still there.
Now, please counter my position with something factual...youtube is a worse reference than wiki. The PM's PROVE that I don't know engineering ?
Would be easy as pie to wheel out the real facts, rather than whisper secrets in each other's ears
Another thought to ponder on the topic...are battleships made of stainless steel, or hot dip galvanised ?
shannow -- I don't know why, from time to time, you choose to spar with a few of bitog's mental giants.
methinks a hissy fit will happen. they're always comical.
have a good day.
Originally Posted by StevieC
There is quite a few that think otherwise. I got PM's to prove it. But we'll leave that discussion for PM only.
I think this thread is done unless anyone else has anything to add to the Rebar discussion.
Ohhh, the dreaded PM "list"...there used to be a troll blog for the mechanically illiterate out there somewhere, where they would sit around, and circle...well you know what...about how mean and nasty certain posters are.
Not sure if it's still extant, but you could ask your mechanically illiterate pals via PM is it's still there.
Now, please counter my position with something factual...youtube is a worse reference than wiki. The PM's PROVE that I don't know engineering ?
Would be easy as pie to wheel out the real facts, rather than whisper secrets in each other's ears
Another thought to ponder on the topic...are battleships made of stainless steel, or hot dip galvanised ?
shannow -- I don't know why, from time to time, you choose to spar with a few of bitog's mental giants.
methinks a hissy fit will happen. they're always comical.
have a good day.
My non-engineering thoughts are that coated rebar is a solution to a problem that could be resolved by itself. The steel the rebar is made from is important here. I have seen cheap Chinese steel rebar that bends like a washrag while handling.
It seems to me that this epoxy coat could hide problems. If the steel underneath was not perfectly cleaned of corrosion and oils prior to coating then all that has happened is that the problem is hiding underneath the coating.
Commenting on that parking lot picture; if there is a rebar sticking out of the pavement then that is a sign of a very poor job indeed. How many people need to trip over that before someone just goes out and cuts it back?
It seems to me that this epoxy coat could hide problems. If the steel underneath was not perfectly cleaned of corrosion and oils prior to coating then all that has happened is that the problem is hiding underneath the coating.
Commenting on that parking lot picture; if there is a rebar sticking out of the pavement then that is a sign of a very poor job indeed. How many people need to trip over that before someone just goes out and cuts it back?
Yeah we have been complaining about it since the summer, and now that the winter is here and the plows have been running over it and they have been salting which is causing freeze/thaw cycles on the concrete around it, more is exposed now and it could easily catch someones tire the wrong way.
It's the landlord they just don't care. We have had one of our furnaces down since September and been waiting on them to fix the exhaust pipe in the roof and it's still not fixed yet so the other furnaces have to overheat their spaces to keep this other middle space warm.
It's the landlord they just don't care. We have had one of our furnaces down since September and been waiting on them to fix the exhaust pipe in the roof and it's still not fixed yet so the other furnaces have to overheat their spaces to keep this other middle space warm.
The construction industry has no interest in building bridges that will last forever or anywhere close to that long. Any improvement in technology that increases the usable life of the structure without a corresponding increase in construction / maintenance costs is a threat to their profits.
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Originally Posted by StevieC
Yeah we have been complaining about it since the summer, and now that the winter is here and the plows have been running over it and they have been salting which is causing freeze/thaw cycles on the concrete around it, more is exposed now and it could easily catch someones tire the wrong way.
It's the landlord they just don't care. We have had one of our furnaces down since September and been waiting on them to fix the exhaust pipe in the roof and it's still not fixed yet so the other furnaces have to overheat their spaces to keep this other middle space warm.
I would just go out and cut it out.
Yeah we have been complaining about it since the summer, and now that the winter is here and the plows have been running over it and they have been salting which is causing freeze/thaw cycles on the concrete around it, more is exposed now and it could easily catch someones tire the wrong way.
It's the landlord they just don't care. We have had one of our furnaces down since September and been waiting on them to fix the exhaust pipe in the roof and it's still not fixed yet so the other furnaces have to overheat their spaces to keep this other middle space warm.
I would just go out and cut it out.
Originally Posted by mk378
The construction industry has no interest in building bridges that will last forever or anywhere close to that long. Any improvement in technology that increases the usable life of the structure without a corresponding increase in construction / maintenance costs is a threat to their profits.
That's part of it....look at the Roman Concrete, although it was a different chemistry, using ash based pozzolanic materials rather than Portland cement....they will still be standing after our cities crumble.
Move onto Portland Cement, our modern technology.
Take the Hoover Dam, or any of the 30s and 40s infrastructure that our various countries built....the cement powder back in those days was extremely coarsely ground, meaning that the cementitious reactions were slow, and to get the 28 day strength required a LOT of cement....and as the concrete ages, it just gets stronger and stronger. When I was working with Oz's foremost Concrete scientist on specific issues that we were having at the time, he explained that they had seen old structures that had attained 60 or 70MPA strengths over time.
You've undoubtedly seen evidence of this....old water tanks and towers in particular, you can see where they have cracked, started to leak, and self healed, as the unreacted cement comes into play.
Modern techniques, with ultra fine milling reach their 28 day strength, and have neither the reserve alkalinity to keep getting stronger, but also resist chemical attack and carbonation...they won't self heal, and they won't be here in 1,000 years time.
Throw in lack of adequate cover over the rebar, and spalling occurs in decades, if not sooner.
The construction industry has no interest in building bridges that will last forever or anywhere close to that long. Any improvement in technology that increases the usable life of the structure without a corresponding increase in construction / maintenance costs is a threat to their profits.
That's part of it....look at the Roman Concrete, although it was a different chemistry, using ash based pozzolanic materials rather than Portland cement....they will still be standing after our cities crumble.
Move onto Portland Cement, our modern technology.
Take the Hoover Dam, or any of the 30s and 40s infrastructure that our various countries built....the cement powder back in those days was extremely coarsely ground, meaning that the cementitious reactions were slow, and to get the 28 day strength required a LOT of cement....and as the concrete ages, it just gets stronger and stronger. When I was working with Oz's foremost Concrete scientist on specific issues that we were having at the time, he explained that they had seen old structures that had attained 60 or 70MPA strengths over time.
You've undoubtedly seen evidence of this....old water tanks and towers in particular, you can see where they have cracked, started to leak, and self healed, as the unreacted cement comes into play.
Modern techniques, with ultra fine milling reach their 28 day strength, and have neither the reserve alkalinity to keep getting stronger, but also resist chemical attack and carbonation...they won't self heal, and they won't be here in 1,000 years time.
Throw in lack of adequate cover over the rebar, and spalling occurs in decades, if not sooner.
Originally Posted by StevieC
From an Engineering Journal
Another link from another source: https://www.sciencedirect.com/topics/engineering/rebar-corrosion
And another: https://www.cement.org/learn/concrete-technology/durability/corrosion-of-embedded-materials
OOHHHH you can use google...your mailing list must be proud of you.
That's the problem with these "debates"...you go doctor google, when you don't have the faintest idea on what a pozzolanic property is, then get all huffy....time and time over.
I can't engage in discourse, as you haven't the faintest idea on what you are talking about (authoratively I might add) in the first place.
From an Engineering Journal
Another link from another source: https://www.sciencedirect.com/topics/engineering/rebar-corrosion
And another: https://www.cement.org/learn/concrete-technology/durability/corrosion-of-embedded-materials
OOHHHH you can use google...your mailing list must be proud of you.
That's the problem with these "debates"...you go doctor google, when you don't have the faintest idea on what a pozzolanic property is, then get all huffy....time and time over.
I can't engage in discourse, as you haven't the faintest idea on what you are talking about (authoratively I might add) in the first place.
Per the links provided...LOLing at the first one I looked at....
https://www.sciencedirect.com/topics/engineering/rebar-corrosion
Quote
Chloride-induced rebar corrosion results mainly from the use of deicing salts in cold climates and/or exposure to marine environments. When concrete undergoes alternate wetting and drying, the water, which contains chlorides, can penetrate through concrete and cause concrete deterioration. This is called a chloride attack. Chloride ions can enter concrete in two ways: they may be added during mixing either deliberately as an admixture or as a contaminant in the original constituents. Calcium chloride has been used as an admixture in the past because it is relatively cheap, accelerates setting, and provides early strength in concrete. The corrosive effects of chloride were not observed until 20 years after the application of calcium chloride, when it had already caused some damage to hydropower structures.
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.There are generally two ways to prevent a chloride attack. The first method involves enhancing the quality of concrete (e.g., by choosing proper materials, having adequate cover over reinforcements, paying attention to the environmental changes during construction) and concrete coating.
Oooh, there's that "design" word.
From the "Engineering Journal"....firstly, here's it's full title....Effect of Chloride and Corrosion of Reinforcing Steel on Thermal Behavior of Concrete and its Modeling
So while the shortened name provided would appear t be a discussion on chloride attacks, it's actually a paper on using thermography to identify corroded rebar...
https://www.sciencedirect.com/topics/engineering/rebar-corrosion
Quote
Chloride-induced rebar corrosion results mainly from the use of deicing salts in cold climates and/or exposure to marine environments. When concrete undergoes alternate wetting and drying, the water, which contains chlorides, can penetrate through concrete and cause concrete deterioration. This is called a chloride attack. Chloride ions can enter concrete in two ways: they may be added during mixing either deliberately as an admixture or as a contaminant in the original constituents. Calcium chloride has been used as an admixture in the past because it is relatively cheap, accelerates setting, and provides early strength in concrete. The corrosive effects of chloride were not observed until 20 years after the application of calcium chloride, when it had already caused some damage to hydropower structures.
.
.
.There are generally two ways to prevent a chloride attack. The first method involves enhancing the quality of concrete (e.g., by choosing proper materials, having adequate cover over reinforcements, paying attention to the environmental changes during construction) and concrete coating.
Oooh, there's that "design" word.
From the "Engineering Journal"....firstly, here's it's full title....Effect of Chloride and Corrosion of Reinforcing Steel on Thermal Behavior of Concrete and its Modeling
So while the shortened name provided would appear t be a discussion on chloride attacks, it's actually a paper on using thermography to identify corroded rebar...
Originally Posted by StevieC
There is quite a few that think otherwise. I got PM's to prove it. But we'll leave that discussion for PM only.
I give up with you... I'm going to put you on ignore.
Willed Ignorance
Description: Refusing to change one's mind or consider conflicting information based on a desire to maintain one's existing beliefs.
Logical Form:
I believe X.
You have evidence for Y.
I don't want to see it because I don't want to stop believing in X.
Example #1:
I don't want anything coming in the way of me and my beliefs; therefore, I will only socialize with people who share my beliefs.
Explanation: This is a common form of the fallacy -- excluding oneself from society as a whole to smaller subgroups where the same general opinions are shared.
Example #2:
I know what I know, and I refuse to debate!
Explanation: Refusing to "debate", or consider other information is a refusal to reason.
Ed
There is quite a few that think otherwise. I got PM's to prove it. But we'll leave that discussion for PM only.
I give up with you... I'm going to put you on ignore.
Willed Ignorance
Description: Refusing to change one's mind or consider conflicting information based on a desire to maintain one's existing beliefs.
Logical Form:
I believe X.
You have evidence for Y.
I don't want to see it because I don't want to stop believing in X.
Example #1:
I don't want anything coming in the way of me and my beliefs; therefore, I will only socialize with people who share my beliefs.
Explanation: This is a common form of the fallacy -- excluding oneself from society as a whole to smaller subgroups where the same general opinions are shared.
Example #2:
I know what I know, and I refuse to debate!
Explanation: Refusing to "debate", or consider other information is a refusal to reason.
Ed
I kind of liked the idea of stainless steel rebar, I didn't ever think it though that such a thing existed. One site I ran across even had a Milwaukee bridge/overpass project in their gallery:
https://stainlessrebar.com
This isn't the Milwaukee project but wow:
https://stainlessrebar.com
This isn't the Milwaukee project but wow:
Originally Posted by kschachn
I kind of liked the idea of stainless steel rebar, I didn't ever think it though that such a thing existed. One site I ran across even had a Milwaukee bridge/overpass project in their gallery:
https://stainlessrebar.com
This isn't the Milwaukee project but wow:
I'm sure on a project like this Stainless adds some cost and it might be easily absorbed versus a long bridge with lots and lots of rebar and I think as well there isn't enough stainless production in order to fulfill the need for it in projects everywhere chlorides are a concern as per the video. I can't confirm this but it seems logical.
I kind of liked the idea of stainless steel rebar, I didn't ever think it though that such a thing existed. One site I ran across even had a Milwaukee bridge/overpass project in their gallery:
https://stainlessrebar.com
This isn't the Milwaukee project but wow:
I'm sure on a project like this Stainless adds some cost and it might be easily absorbed versus a long bridge with lots and lots of rebar and I think as well there isn't enough stainless production in order to fulfill the need for it in projects everywhere chlorides are a concern as per the video. I can't confirm this but it seems logical.
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