What did you buy this week?

[scootr]

Well, 6" is the standard for anything that gets vehicles on it. Yes, sidewalk does "generally" hold up to passenger vehicles; but if you see any area where people frequently park/drive over, 4" is generally cracked up.

PT, cause its $10.40/each; vs $8.15/each not PT; and no, definitely not leaving in place. Figure, I need to reuse these for the next two pours, and whatever afterwards; not worth the trouble of saving $12

That's all good.
I'm saying I've poured a miles of 4" drives and parking pads, garages that are still good 50 yrs later. Talk to your batch plant to get 3k psi mud and insert wire or add fiber.
I'm not judging. I'm just saying it's not necessary.

 

[MossRoad]

Thank you for noticing Arthur.

 

[joeyd]

I bought or should I say my extended warranty is buying a new passenger side exhaust manifold for my 2019 Dodge Ram. I bought the after market warranty that my credit union offered, way cheaper that the dealer. They wouldn't do both sides.

 

[paulsharvey]

That's all good.
I'm saying I've poured a miles of 4" drives and parking pads, garages that are still good 50 yrs later. Talk to your batch plant to get 3k psi mud and insert wire or add fiber.
I'm not judging. I'm just saying it's not necessary.

Everything work related, that takes traffic, 6", 3000 psi, no wire/fiber; actually Travel lanes are 8" and have rebar mat.

Ive also demo'd a lot of concrete, and 4" sidewalk, once you get a side up, breaks pretty easily with a 8# sledge; 6" without wire takes some beating with a back hoe bucket; 6" with wire; takes a Lot of beating... With rebar mat, time to call a specially concrete cutting sub

 

[dnw64]

'm saying I've poured a miles of 4" drives and parking pads, garages that are still good 50 yrs later. Talk to your batch plant to get 3k psi mud and insert wire or add fiber.

High strength concrete, with wire/fiber is a necessity. BUT so is, a proper base. Put that on quicksand and you will have gravel before you know it.

I have a brother-in-law that does precast for the state (NJ and PA, maybe DE) , and two nephews that do pour-in-place for Amazon and the like. Proper prep is 100% key.

 

[paulsharvey]

Not to go too far down the concrete rabbit hole, But; Many people who pour concrete dont actually understand/care how it actually works. You take a normal 3000 psi, standard rock concrete, designed to be poured at a 5" slump; dump 40 gal of water to get it to an 8" slump; and i really think a lot of folks dont understand the affect that has. Not to mention, id rather pull stiff mud down hill, than wet mud Up hill....

Yes, there are mixes designed to be poured at a 9-10" slump, like drilled shaft mud, but its Designed that way;

Yes, you can chase some water out of a form with the concrete, with minor effects; but there are absolutely guys that will dump into a 20" thick edge, that has 20" of water in it...

As pointed out, 4" of Good concrete, over compacted, 95% density, suitable material, is better than 6" of wet crap, over muck ... With that, any official design I've ever seen that involves traffic loads, its 6".

 

[scootr]

We used to pour 3k psi building slabs and 2.5k psi flatwork on the same day. All the truck tickets came to me when the pours were done. The slab guy handed me a stack of tickets and I these can't be yours. He insisted they were. Well, I said you poured 2500 psi mud in that slab. 30 days passed and the cylinder break tests read 2600 psi. We waited another month and the test came up to 3200 psi. Conc keeps getting harder with age....

 

[paulsharvey]

We used to pour 3k psi building slabs and 2.5k psi flatwork on the same day. All the truck tickets came to me when the pours were done. The slab guy handed me a stack of tickets and I these can't be yours. He insisted they were. Well, I said you poured 2500 psi mud in that slab. 30 days passed and the cylinder break tests read 2600 psi. We waited another month and the test came up to 3200 psi. Conc keeps getting harder with age....

So, I have Often seen 3000# mix break at 28 days at 3,800-4300. They absolutely include a safety factor. We also had an incident once with 3000# mix, that broke before a readable number... just crumbled. That was on a 3 story student housing building; and was a major ordeal. Luckily we had a testing guy, that recorded any water added; pulled slump, air, and 7/14/28/hold cylinders.

If I remember right, (I was just an assistant super on this job), the concrete company's starting offer was price of the concrete, what a joke; i believe they ended up paying for the demo, and the 1st bad batches; but i think we ate all the form/pour labor

 

[Engineer42]

Everything work related, that takes traffic, 6", 3000 psi, no wire/fiber; actually Travel lanes are 8" and have rebar mat.

Ive also demo'd a lot of concrete, and 4" sidewalk, once you get a side up, breaks pretty easily with a 8# sledge; 6" without wire takes some beating with a back hoe bucket; 6" with wire; takes a Lot of beating... With rebar mat, time to call a specially concrete cutting sub

Sub grade also makes a difference. A sandy, or silty clay sub grade with a higher water table will require a thicker pavement section than building in a rocky, west coast area.

That's why fed projects out west can build concrete highways with a lower sack count out west, and why they have been proven not to work in the middle Atlantic/Southern coastal States.

 

[Engineer42]

We used to pour 3k psi building slabs and 2.5k psi flatwork on the same day. All the truck tickets came to me when the pours were done. The slab guy handed me a stack of tickets and I these can't be yours. He insisted they were. Well, I said you poured 2500 psi mud in that slab. 30 days passed and the cylinder break tests read 2600 psi. We waited another month and the test came up to 3200 psi. Conc keeps getting harder with age....

And I would not have paid for the concrete. There's more to the psi difference then break range. If done right you can get 2000psi mix to break above 3k.

Mix designs, how much cement, which stone, sand amounts, add mixes, they all figure in.

Sorry, that would be like drywalling a house with 1/2" and charging for 3/4" fireproof. Looks the same, but not what I paid for.

Bucks is bucks.

 

[scootr]

It wasn't my money or my decision to make but point well taken.

 

[bigtiller]

And I'd would not have paid for the concrete. There's more to the psi difference then break range. If done right you can get 2000psi mix to break above 3k.

Mix designs, how much cement, which stone, sand amounts, add mixes, they all figure in.

Sorry, that would be like drywalling a house with 1/2" and charging for 3/4" fireproof. Looks the same, but not what I paid for.

Bucks is bucks.

Yep, what he said.
Good times brought more and stronger concrete.
When I was a teenager, all DIY'ers around here used a gravel aggregate and 2500 psi. for sidewalks...very few could afford a concrete driveway.

But a decade or two later everyone switched to limestone and 3000 with some at 3500 psi. and were pouring driveways 4" thick.

 

[dodge man]

I can’t remember where I worked ever specing less than 3000 psi and sometimes 4000 psi. I broke hundreds of cylinders over the years. The machine has a cage around it but shards can still go flying. I could tell when a cylinder was going to break high and I’d get as far away as I could. I think I saw break as high as 8000 psi once in a while.

The one time I remember low breaks was when the air content was high. The owner wanted to know why I let them pour it. As an inspector I have no control or authority on the job. I told the contractor the air was really high on that load, they elected to use it anyway.

I personally would never use 4” thick anywhere but sidewalk.

 

[paulsharvey]

FDOT Type-I Non-structural concrete (NS) has a min 28 day break of 2500 PSI. It often breaks at 4000+. Used in sidewalks, driveways, ect. It's also a fairly old school concrete, and although every batch plant has its own mix design to meet the spec; it's more or less just Portland cement, sand, water, and gravel. Less fly-ash, and other ad-mixes than most other "commercial" 3000 psi mixes.

Sometimes simple is best... Not every mix needs super plastizier, or calcium, or whatever, and often, those "fancy" mixes have draw backs for long term

 

[paulsharvey]

Wow, this went further down the concrete rabbit hole then intended; but i was just reading the 25-26 spec book, and RAP (asphalt millings) are now allowed to make up upto 20% of the aggregate in non structural Portland cement concrete. That's an odd choice....

 

[Engineer42]

Wow, this went further down the concrete rabbit hole then intended; but i was just reading the 25-26 spec book, and RAP (asphalt millings) are now allowed to make up upto 20% of the aggregate in non structural Portland cement concrete. That's an odd choice....View attachment 4047518

that's how I would prefer it to be used in Hot Mix, as aggregate with no asphalt value.

I prefer virgin mixes with no rap. I feel that assigned asphalt content in RAP is often rated too high, leading to dryer mixes.

Just my opinion.

 

[grsthegreat]

If i ever poured a new garage floor or parking ribbon id go minimum 6”. Im so sick and tired of concrete cracking.

If i replace the slab where i park my tractor, its going to be 6” with steel plates that allign with tires so the chains wont damage concrete.

 

[ArlyA]

Speaking of concrete. We have a locale co who makes carbon fiber rebar. If you go to road or bridge construction site in many states, they are now required to use coated rebar to keep in from rusting because of road salt.

 

[dnw64]

At the dealer getting a replacement key programmed. $717.69 for the key and programming...

(Porsche)

 

[kenmbz]

At the dealer getting a replacement key programmed. $717.69 for the key and programming...

(Porsche)

Wow, for what 15 minutes of work and a $50 key?