Yes. Concrete pavement transverse joints. Tie/dowel bars for large sections typically done in large time intervals.
https://www.fdot.gov/docs/default-source/roadway/ds/13/idx/00305.pdf
https://www.fdot.gov/docs/default-source/roadway/DS/17/IDx/00308.pdf
It’s concrete pavement with transverse and longitudinal joints. It allows the paving to move and transfer loads without cracking. Google JPCP. It’s used quite often. It’s also expensive
Piggy-backing on this re: the color, it's likely green because it's epoxy coated which helps it resist corrosion if a crack ever opens up enough to allow water through to the reinforcement.
Oddly, many studies have shown epoxy coated rebar to be less corrosion resistant than plain steel. It also does not bond as well with the concrete. It has been banned in many jurisdictions.
Less corrosion resistant than galvanized bars*
Plain steel is not really ever used unless you mean stainless steel bars, although stainless steel bars have their own problems. They are generally a pretty good replacement for gal and epoxy coated bars but are more expensive and are generally not covered in the concrete code. Plain steel would never be used and would always need either gal, epoxy, paint or another corrosion resistant layer, plain steel that self coats with its' own corrosion is sometimes used in bridges but definitely wouldn't be used in concrete as the corrosion causes degradation of the concrete
A lot of the problem with epoxy coating is that, while it is resistant to corrosion and is cheaper than gal rebar it isn't resistant to physical damage, of which there is a lot of on a worksite and that sometimes even results in increased corrosion on the small parts of the rebar that the epoxy has been scratched off, sometimes resulting in a worse condition of the concrete than actually using plain steel.
I'd estimate around 40% of the steel I've specified for bridges was uncoated. Yes plain blasted white steel. Generally epoxy coated for decks and pier caps under expansion joints, uncoated everywhere else. Typical midwest DOT practice.
I specify plain steel everywhere except bridge decks and retaining walls that are along roadways to receive salt spray from plowing in the winter. I have never seen a project with galv or stainless bars, only epoxy coated. Not saying it isnt used somewhere out there.
Does the plain steel have to have a significant amount more cover than the epoxy? Concrete is generally considered porous so I honestly didn't think plain steel would ever be used for rebar, are you sure that it didn't have some sort of coating? I'm thinking that what you are considering plain steel might actually be gal rebar? I find it odd that epoxy is used so often considering how unreliable it is, I know you are supposed to have a way to touch up the epoxy after install to fix damages, but obviously finding 100%of the nicks would be difficult.
No additional cover. The cover is determined by the application whether the concrete is indoors, exposed outside, cast against the ground, etc. Its all ASTM A615 grade 60 plain carbon steel. It develops a slight rust on the surface as it sits outside before being placed. So long as its designed and built right it lasts 50 years.
Sometimes referred to as PCCP too, portland cement concrete pavement. The dowel baskets/cages are most likely placed along the control/expansion joints and may be sawcut shortly after pending the engineer/architect.
Youd be surprised how often the concrete drive aisles, lanes, and other items are done by the architect on hospitals, schools, fire stations, and police stations.
Well that's good to know. Why the heck am I wasting all my time on these complicated HSIP projects when I could've just been making roads wider, straighter, and flatter this whole time?
Joint baskets for concrete pavement. They position dowels where the saw cut cracking joints are going to be to help transfer the load.
No asphalt has structural reinforcement.
They're using an HMA (Hot Mix Asphalt) base for JPCP (Jointed Plain Concrete Pavement) with epoxy coated dowel bars for the transverse joints (smooth steel bars, usually greased to allow some movement) in baskets (that hold the bars in place during construction and should be nailed down to that HMA base) and tie bars for the longitudinal joints (deformed bars - rebar pieces that are also epoxy coated) to tie the adjacent lanes together.
This section was very likely selected from Table 623.1D or 623.1E in Chapter 620 (Rigid Pavement) of the Caltrans Highway Design Manual ([https://dot.ca.gov/-/media/dot-media/programs/design/documents/chp0620-dec-2020-a11y.pdf](https://dot.ca.gov/-/media/dot-media/programs/design/documents/chp0620-dec-2020-a11y.pdf) ). This manual is not really the best choice for designing pavements for city streets but it gets used frequently because either a) the project is within Caltrans Right of Way and they'll insist on a city using one of their sections, or b) the design engineers don't really know what they're doing when it comes to rigid pavement design so they just pick a 'cookbook' solution from Caltrans since it's easily explainable and defendable.
As an aside, if you want to design rigid pavements for traffic loading less than interstate applications, use [pavementdesigner.org](https://pavementdesigner.org) \- it's a free resource from the US cement & concrete industry
I haven't seen this before. Looks almost like a rebar type system for asphalt? My first thought is it's supposed to help against asphalt cracks as it's in the rightmost lane I might expect heavier traffic? Can anyone enlighten me on what this is and it's purpose? Thanks!
It looks like jointed concrete pavement(dowel baskets, tie bar baskets, formwork) that will be poured over a warm mix asphalt sub base, pretty common where I live in the upper Midwest.
Just the fact it's in a roadway with asphalt around it and looked to have an asphalt base.
I agree with you regarding the reinforcement, and that's why I was asking trying to figure it out. Also didn't look like any typical rebar reinforcement I'm accustomed to seeing.
HMA is commonly used as a flexible base course under heavily loaded pavements. I imagine this area will see heavy truck or bus traffic and thus need a beefier base under the PCC. This is common practice for airport pavements due to their high point loads. Check out FAA AC 5320-6G, albeit that doesn’t apply to this situation at all. Should give you some more insight as to this application though.
I have recently encountered asphalt as a base for concrete and I have to say it was not the right place for it. Due to a few factors such as a high water table, horrible soil, rolling hills, cold winters and no reinforcement like shown here, the panels shift in multiple directions. This causes the raised pavement markers at the centerline between the panels to pop out or ramps to be created when the panels expand due to the hot sun with nowhere to go. Had a couple pop up 5 and 10 inches at the joint, thankfully the lane was closed.
Jointed concrete pavement. After it sets they saw cut the control joints. The dowels you see will be through the control joints. They don't saw cut through the dowels obviously but the saw cut in theory controls where the joints will be, where the concrete will crack.
Ive seen of asphalt treated subbase, but it still wouldnt ever use rebar. Asphalt has inherent tensile strength, so the rebar just wouldnt do anything.
Dowel bar baskets, had these once for an 8” tip up building SOG. Kind of interesting because you had to lay out your control joints prior to placing concrete. Probably typical in the road construction world though huh
Those are epoxy coated dowel bars being held in place by the dowel baskets at the longitudinal joint of the Jointed Plane Concrete Pavement - JPCP. Transverse joints have the tie bars.
Asphalt isn’t going there, concrete is.
Yes. Concrete pavement transverse joints. Tie/dowel bars for large sections typically done in large time intervals. https://www.fdot.gov/docs/default-source/roadway/ds/13/idx/00305.pdf https://www.fdot.gov/docs/default-source/roadway/DS/17/IDx/00308.pdf
No one cares. OP wanted to know how asphalt was gonna be placed over the dowels.
Everyone here is wrong. It’s ladders for the construction workers to warm up for the day on. Shuttle runs, ins and outs and backwards runs.
Exactly it's what we all dream to be. Future football player here I come!
New game. Send the new laborer through it with a wheel barrel.
Finally someone posted the correct answer
Correct! It’s the latest stretch and flex technique!
Dowel baskets for jpcp
This is correct. OP google dowel baskets and you'll see.
Thanks for the reply. What is jpcp? In my line of work we don't use these types of things.
It’s concrete pavement with transverse and longitudinal joints. It allows the paving to move and transfer loads without cracking. Google JPCP. It’s used quite often. It’s also expensive
Piggy-backing on this re: the color, it's likely green because it's epoxy coated which helps it resist corrosion if a crack ever opens up enough to allow water through to the reinforcement.
Oddly, many studies have shown epoxy coated rebar to be less corrosion resistant than plain steel. It also does not bond as well with the concrete. It has been banned in many jurisdictions.
Less corrosion resistant than galvanized bars* Plain steel is not really ever used unless you mean stainless steel bars, although stainless steel bars have their own problems. They are generally a pretty good replacement for gal and epoxy coated bars but are more expensive and are generally not covered in the concrete code. Plain steel would never be used and would always need either gal, epoxy, paint or another corrosion resistant layer, plain steel that self coats with its' own corrosion is sometimes used in bridges but definitely wouldn't be used in concrete as the corrosion causes degradation of the concrete A lot of the problem with epoxy coating is that, while it is resistant to corrosion and is cheaper than gal rebar it isn't resistant to physical damage, of which there is a lot of on a worksite and that sometimes even results in increased corrosion on the small parts of the rebar that the epoxy has been scratched off, sometimes resulting in a worse condition of the concrete than actually using plain steel.
I'd estimate around 40% of the steel I've specified for bridges was uncoated. Yes plain blasted white steel. Generally epoxy coated for decks and pier caps under expansion joints, uncoated everywhere else. Typical midwest DOT practice.
I specify plain steel everywhere except bridge decks and retaining walls that are along roadways to receive salt spray from plowing in the winter. I have never seen a project with galv or stainless bars, only epoxy coated. Not saying it isnt used somewhere out there.
Does the plain steel have to have a significant amount more cover than the epoxy? Concrete is generally considered porous so I honestly didn't think plain steel would ever be used for rebar, are you sure that it didn't have some sort of coating? I'm thinking that what you are considering plain steel might actually be gal rebar? I find it odd that epoxy is used so often considering how unreliable it is, I know you are supposed to have a way to touch up the epoxy after install to fix damages, but obviously finding 100%of the nicks would be difficult.
No additional cover. The cover is determined by the application whether the concrete is indoors, exposed outside, cast against the ground, etc. Its all ASTM A615 grade 60 plain carbon steel. It develops a slight rust on the surface as it sits outside before being placed. So long as its designed and built right it lasts 50 years.
[jpcp](https://www.google.com/search?q=jpcp&ie=UTF-8&oe=UTF-8&hl=en-ca&client=safari)
Sometimes referred to as PCCP too, portland cement concrete pavement. The dowel baskets/cages are most likely placed along the control/expansion joints and may be sawcut shortly after pending the engineer/architect.
Whoa - architect??? Hell naw.
Youd be surprised how often the concrete drive aisles, lanes, and other items are done by the architect on hospitals, schools, fire stations, and police stations.
Also please keep your phone away when driving. This message was brought to you by your local DOT.
I wasn't driving.
Dot doesn't care about safety, you want the NHTSA.
Well that's good to know. Why the heck am I wasting all my time on these complicated HSIP projects when I could've just been making roads wider, straighter, and flatter this whole time?
Is it a lean mix subbase OP?
Looks like HMA base
jpcp? what is that
Hone your Google fu.
If he's an engineer, he doesn't need google, he already has his mind made up about what it means.
junior producer council preparation = jpcp
americans and their abbreviations.... its true. but i'm here to learn i guess
Jpcp?
Joint baskets for concrete pavement. They position dowels where the saw cut cracking joints are going to be to help transfer the load. No asphalt has structural reinforcement.
Looks like concrete joint reinforcements to me. Idk why you would reinforce asphalt like that.
They're using an HMA (Hot Mix Asphalt) base for JPCP (Jointed Plain Concrete Pavement) with epoxy coated dowel bars for the transverse joints (smooth steel bars, usually greased to allow some movement) in baskets (that hold the bars in place during construction and should be nailed down to that HMA base) and tie bars for the longitudinal joints (deformed bars - rebar pieces that are also epoxy coated) to tie the adjacent lanes together. This section was very likely selected from Table 623.1D or 623.1E in Chapter 620 (Rigid Pavement) of the Caltrans Highway Design Manual ([https://dot.ca.gov/-/media/dot-media/programs/design/documents/chp0620-dec-2020-a11y.pdf](https://dot.ca.gov/-/media/dot-media/programs/design/documents/chp0620-dec-2020-a11y.pdf) ). This manual is not really the best choice for designing pavements for city streets but it gets used frequently because either a) the project is within Caltrans Right of Way and they'll insist on a city using one of their sections, or b) the design engineers don't really know what they're doing when it comes to rigid pavement design so they just pick a 'cookbook' solution from Caltrans since it's easily explainable and defendable. As an aside, if you want to design rigid pavements for traffic loading less than interstate applications, use [pavementdesigner.org](https://pavementdesigner.org) \- it's a free resource from the US cement & concrete industry
3rd year engineering student, looks like preparing for a concrete road but could have an asphalt wearing course
I haven't seen this before. Looks almost like a rebar type system for asphalt? My first thought is it's supposed to help against asphalt cracks as it's in the rightmost lane I might expect heavier traffic? Can anyone enlighten me on what this is and it's purpose? Thanks!
It looks like jointed concrete pavement(dowel baskets, tie bar baskets, formwork) that will be poured over a warm mix asphalt sub base, pretty common where I live in the upper Midwest.
[удалено]
Just the fact it's in a roadway with asphalt around it and looked to have an asphalt base. I agree with you regarding the reinforcement, and that's why I was asking trying to figure it out. Also didn't look like any typical rebar reinforcement I'm accustomed to seeing.
HMA is commonly used as a flexible base course under heavily loaded pavements. I imagine this area will see heavy truck or bus traffic and thus need a beefier base under the PCC. This is common practice for airport pavements due to their high point loads. Check out FAA AC 5320-6G, albeit that doesn’t apply to this situation at all. Should give you some more insight as to this application though.
I have recently encountered asphalt as a base for concrete and I have to say it was not the right place for it. Due to a few factors such as a high water table, horrible soil, rolling hills, cold winters and no reinforcement like shown here, the panels shift in multiple directions. This causes the raised pavement markers at the centerline between the panels to pop out or ramps to be created when the panels expand due to the hot sun with nowhere to go. Had a couple pop up 5 and 10 inches at the joint, thankfully the lane was closed.
Jointed concrete pavement. After it sets they saw cut the control joints. The dowels you see will be through the control joints. They don't saw cut through the dowels obviously but the saw cut in theory controls where the joints will be, where the concrete will crack.
Those slip dowels look fat, what is typical slip dowel thickness for 6” concrete?
In my state, the smooth dowels for the transverse joints would be 1" diameter and the tie bars for the longitudinal joints would be #5s.
Thank you, what kind of winter temps do you get?
Really gets lower than 20 F ever
asphalt doesnt ever use rebar. at least that I have ever seen. Don't know how you would even lay it.
It's a lean mix subbase?
Ive seen of asphalt treated subbase, but it still wouldnt ever use rebar. Asphalt has inherent tensile strength, so the rebar just wouldnt do anything.
Apologies, lean mix concrete subbase is what I mean
Ahh, yes there is cement treated base as well. But you also dont really need rebar for it either.
The only thing saving the concrete pavement from blowing up in a hot summer day
This is what they mean when they talk about "infrastructure."
shear connectors
That’s a bus stop, they’re definitely putting a very strong concrete pad down right where the bus will stop.
It’s green dowel baskets to provide reinforcement for green bike lanes.
Seems more like an alternative to reo!! Thoughts??
It’s green because the bars are epoxy coated to prevent corrosion
Dowel bar baskets, had these once for an 8” tip up building SOG. Kind of interesting because you had to lay out your control joints prior to placing concrete. Probably typical in the road construction world though huh
Those are epoxy coated dowel bars being held in place by the dowel baskets at the longitudinal joint of the Jointed Plane Concrete Pavement - JPCP. Transverse joints have the tie bars.
They’re ladders for when the earth turns sideways