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Almost Everything You Need To Know About Concrete

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5 hours ago, impartialobserver said:

What do you know about pouring concrete? (I am being serious)

 

Besides almost everything?

 

Not much.

 

Ha!

 

What would you like to know?

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12 hours ago, Blue Devil said:

 

Besides almost everything?

 

Not much.

 

Ha!

 

What would you like to know?

Others already answered the question but your input would be interesting as well. Going to pour a 4 ft. by 14 ft slab and was curious whether or not, it is necessary to order a truck to come by or not? As of yet, have been doing this whole project alone.

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40 minutes ago, impartialobserver said:

Others already answered the question but your input would be interesting as well. Going to pour a 4 ft. by 14 ft slab and was curious whether or not, it is necessary to order a truck to come by or not? As of yet, have been doing this whole project alone.

 

- Traffic weight 4", or Patio 3" slab?

- What is your reinforcing?

- Sack or mixer w/ constituents?

- Can you do 4'x3.5' expansion panels?

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34 minutes ago, Blue Devil said:

 

- Traffic weight 4", or Patio 3" slab?

- What is your reinforcing?

- Sack or mixer w/ constituents?

- Can you do 4'x3.5' expansion panels?

1. I would assume traffic weight.. going to be where I put a tent trailer

2. Don't know.

3. As of yet, I have no one lined up but could. How many individuals would be needed?

4. Don't know, would have to research this idea more.

 

This project will not get under way until late Sept so this is just thinking ahead and doing research. Thanks for your input

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1 hour ago, impartialobserver said:

1. I would assume traffic weight.. going to be where I put a tent trailer

2. Don't know.

3. As of yet, I have no one lined up but could. How many individuals would be needed?

4. Don't know, would have to research this idea more.

 

This project will not get under way until late Sept so this is just thinking ahead and doing research. Thanks for your input

 

Well...

 

For a 4" slab of that size, you are only lookin' at ~ 3/4 of a yard of concrete w/ overage.

 

No need for a truck, and the short load would be expensive.

 

You can get one yard trailers of ready-mix from some construction equipment rental outfits, but you will have to shop that.

 

Could sack it (60 or 90 lb), w/ a rental mixer. Or, in a wheel barrow, if you feel up to it, depending on the weather.

 

A rental mixer and constituents would work as well.

 

For that, would suggest skip placing 4'x3.5' pads.

 

Place every other two, wait at least three days (seven is better), and then place the remaining two.

 

That way, your placements are small, and the shrinkage won't crack the slabs.

 

Just use continuous reinforcement though the joints.

 

 

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5 minutes ago, Blue Devil said:

 

Well...

 

For a 4" slab of that size, you are only lookin' at ~ 3/4 of a yard of concrete w/ overage.

 

No need for a truck, and the short load would be expensive.

 

You can get one yard trailers of ready-mix from some construction equipment rental outfits, but you will have to shop that.

 

Could sack it (60 or 90 lb), w/ a rental mixer. Or, in a wheel barrow, if you feel up to it, depending on the weather.

 

A rental mixer and constituents would work as well.

 

For that, would suggest skip placing 4'x3.5' pads.

 

Place every other two, wait at least three days (seven is better), and then place the remaining two.

 

That way, your placements are small, and the shrinkage won't crack the slabs.

 

Just use continuous reinforcement though the joints.

 

 

Thanks for the input. I will shop around for the one yard trailer. That seems like a good fit. Trying to save money and hire very few, if any, helpers. 

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14 minutes ago, impartialobserver said:

Thanks for the input. I will shop around for the one yard trailer. That seems like a good fit. Trying to save money and hire very few, if any, helpers. 

 

Hey, if you want to do it on the cheap, and have the time, definitely sack/barrow it, one pad at a time, skipping.

 

You really only need someone on the other end of the rod/screed.

 

Probably just hand finish/broom, so no bull float.

 

 

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19 minutes ago, Blue Devil said:

 

Hey, if you want to do it on the cheap, and have the time, definitely sack/barrow it, one pad at a time, skipping.

 

You really only need someone on the other end of the rod/screed.

 

Probably just hand finish/broom, so no bull float.

 

 

Last one, is reinforcing it with rebar enough or is there a better technique. I am wanting this to last for a very long time. 

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2 hours ago, impartialobserver said:

Last one, is reinforcing it with rebar enough or is there a better technique. I am wanting this to last for a very long time. 

 

Generally, you would put a hoop of 3/8 or 1/2" bar, w/ an 18" overlap at the splices, 2" in from the perimeter, up on dobies, or suspended cantilevered off the form, and 6x6 10x10 welded wire mesh in the field.

 

And then maybe one/8" - 18" rebar dowels, wired on the top of the 6/6 10/10 WW, pinning the joints, unless the mesh is continuous through the joints.

 

Rebar should be near the center, WW mesh closer (1/4 to 1/3 up) to the bottom.

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1 hour ago, Blue Devil said:

 

Generally, you would put a hoop of 3/8 or 1/2" bar, w/ an 18" overlap at the splices, 2" in from the perimeter, up on dobies, or suspended cantilevered off the form, and 6x6 10x10 welded wire mesh in the field.

 

And then maybe one/8" - 18" rebar dowels, wired on the top of the 6/6 10/10 WW, pinning the joints, unless the mesh is continuous through the joints.

 

Rebar should be near the center, WW mesh closer (1/4 to 1/3 up) to the bottom.

Will keep this in mind when I begin this project next month. Thanks for your input. 

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5 hours ago, impartialobserver said:

 I am wanting this to last for a very long time. 

 

The things that make concrete good - are cement content (richness), and slump (water content).

 

Most ready-mix will have enough cement, but you can always "sweeten" it w/ a half-shovel full of cement per barrow load.

 

Minimal additional cost for a reasonable benefit.

 

Slump - denotes the amount a cone of concrete slumps down when placed.

 

The higher the slump - the wetter the mix.

 

Optimum slump is around 3 for placing, but pumping requires higher, like 6.

 

Think about like cottage cheese.

 

The less water, the stronger the concrete and the less it will shrink.

 

It will also produce a good butter, after the bleed water is struck off, to hard top and seal the slab when finishing.

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16 hours ago, Blue Devil said:

 

The things that make concrete good - are cement content (richness), and slump (water content).

 

Most ready-mix will have enough cement, but you can always "sweeten" it w/ a half-shovel full of cement per barrow load.

 

Minimal additional cost for a reasonable benefit.

 

Slump - denotes the amount a cone of concrete slumps down when placed.

 

The higher the slump - the wetter the mix.

 

Optimum slump is around 3 for placing, but pumping requires higher, like 6.

 

Think about like cottage cheese.

 

The less water, the stronger the concrete and the less it will shrink.

 

It will also produce a good butter, after the bleed water is struck off, to hard top and seal the slab when finishing.

About Slump, it would seem that you are saying that I want it slightly wet when mixing or pumping but then enrichening it once it is in the forms?

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5 hours ago, impartialobserver said:

About Slump, it would seem that you are saying that I want it slightly wet when mixing or pumping but then enrichening it once it is in the forms?

 

Nope.

 

Enrich when mixing - and if you are placing it, as opposed to pumping it, it should be fairly dry and stiff, like cottage cheese.

 

You should basically have to work (float) it into place and shape with a shovel, trowel, float, and screed.

 

Just know that when it starts to set - it goes quickly, so don't play around w/ it.

 

Place/float/screed, then wait for the bleed water. Strike that off, edge, and finish.

 

 

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On 8/28/2019 at 6:51 PM, Blue Devil said:

 

Nope.

 

Enrich when mixing - and if you are placing it, as opposed to pumping it, it should be fairly dry and stiff, like cottage cheese.

 

You should basically have to work (float) it into place and shape with a shovel, trowel, float, and screed.

 

Just know that when it starts to set - it goes quickly, so don't play around w/ it.

 

Place/float/screed, then wait for the bleed water. Strike that off, edge, and finish.

 

 

Ball park how much I should have to someone to  prep the ground and install a 40' x 20' concrete slab in my back yard.

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8 hours ago, Skans said:

Ball park how much I should have to someone to  prep the ground and install a 40' x 20' concrete slab in my back yard.

 

Depends on the ground.

 

Describe it.

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On 11/1/2019 at 7:02 PM, Blue Devil said:

 

Depends on the ground.

 

Describe it.

Ground is level and already has concrete pad on it, but it's just deteriorated and cracked. 

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On 11/4/2019 at 5:25 AM, Skans said:

Ground is level and already has concrete pad on it, but it's just deteriorated and cracked. 

 

Well...

 

If you can stand the increase in elevation and the new slab matches the old one - you can slab right over it.

 

If not, it is settled soil, so bust out the old slab, throw a one inch of sand on it as a bond breaker, set your forms and steel, and then just give it a good soaking with a sprayer hose to hydrate and settle the sand before the pour.

 

Don't forget expansion joints.

 

 

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My experience with a concrete pad.  I poured a 8x12 foot 3 inch thick pad for a shed.  I bought a pallet of 42, 80 pound bags of Sackrete from Home Depot as it was much cheaper for an entire pallet than the 30 bags I needed.  It did cost about $30 more than if I had just bought Portland cement and sand/gravel mix from the local gravel pit.  An F-150 does not handle well with 1600 pounds of cargo directly above the rear axle.

 

I used a cheap mixer from Harbor Freight that would handle one 80 pound bag at a time.  I sectioned off the area of the pour to 24 inches at a time so the wet concrete would stay in place for smoothing.  It took me 2 days working alone to pour it all.  No cracks so far even though I store a 700 pound ATV in the shed.

 

The hardest part was leveling the yard where the slab was poured.  I also put about 2 tons of gravel on the ground prior to pouring the concrete.  I let the slab cure for a month in the summer prior to building on it.

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11 hours ago, Blue Devil said:

 

Well...

 

If you can stand the increase in elevation and the new slab matches the old one - you can slab right over it.

 

If not, it is settled soil, so bust out the old slab, throw a one inch of sand on it as a bond breaker, set your forms and steel, and then just give it a good soaking with a sprayer hose to hydrate and settle the sand before the pour.

 

Don't forget expansion joints.

 

 

I intend on busting up the old slab and tossing it.  But, I also intend to pay someone to lay the new slab - about how much should I expect to pay; ballpark?  This is a southern, suburban/rural area; not some big city. 

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11 hours ago, Skans said:

I intend on busting up the old slab and tossing it.  But, I also intend to pay someone to lay the new slab - about how much should I expect to pay; ballpark?  This is a southern, suburban/rural area; not some big city. 

 

Well...

 

Getting competitive bids is the best way to go.

 

Just be sure that they are going to place it with a stiff mix, and not just pour in a self-leveling soup mix.

 

Figure $200/day for the boss, half that per hand - call it $500/day for a four-man crew.

 

If they jack and haul the old slab, and form, reinforce, place and finish the new slab - that's Three, maybe Four days - call it $1,800 labor.

 

Figure:

- $110/yd^3 (81 ft^2 at 4", 108 ft^2 at 3"),

- $120 for a 150' roll of 6x6, 10x10 welded wire reinforcing

- $5/10' stick of 3/8th rebar for the perimeter.

- Mixer or truck a/o pump cost.

- Low bin or dump fee for the old slab

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12 hours ago, Blue Devil said:

 

Well...

 

Getting competitive bids is the best way to go.

 

Just be sure that they are going to place it with a stiff mix, and not just pour in a self-leveling soup mix.

 

Figure $200/day for the boss, half that per hand - call it $500/day for a four-man crew.

 

If they jack and haul the old slab, and form, reinforce, place and finish the new slab - that's Three, maybe Four days - call it $1,800 labor.

 

Figure:

- $110/yd^3 (81 ft^2 at 4", 108 ft^2 at 3"),

- $120 for a 150' roll of 6x6, 10x10 welded wire reinforcing

- $5/10' stick of 3/8th rebar for the perimeter.

- Mixer or truck a/o pump cost.

- Low bin or dump fee for the old slab

Thanks BD, ^^^^^ is VERY helpful!  I am figuring between 3K - 5K. 

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On 11/7/2019 at 5:42 AM, Skans said:

Thanks BD, ^^^^^ is VERY helpful!  I am figuring between 3K - 5K. 

 

There are also incidentals like rebar dobies, tie wire, form stakes, etc...

 

Also possibly a hammer and compressor rental for jackin' the old slab.

 

What are the dimensions of both the old and new slabs?

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16 hours ago, Blue Devil said:

 

There are also incidentals like rebar dobies, tie wire, form stakes, etc...

 

Also possibly a hammer and compressor rental for jackin' the old slab.

 

What are the dimensions of both the old and new slabs?

The rough dimensions are 40' x 20'.  Just replacing a badly cracked up old slab with a new one which hopefully won't crack.

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On 11/11/2019 at 5:46 AM, Skans said:

The rough dimensions are 40' x 20'.  Just replacing a badly cracked up old slab with a new one which hopefully won't crack.

 

Concrete... cracks. And hope doesn't do a damn thing.

 

8>)

 

- Stiff (< 4" slump, or 1 gal. water/Yd^3/ additional 1" slump)

- Rich (3K psi mix for foot, 4K psi mix for traffic)

- Reinforced (6x6/10x10 WW mesh w/ 3/8" perimeter rebar)

- Controlled

 

 

faq_joints_19166.jpg?sfvrsn=61b232bf_2

 

Feet/joint

joints_fig1b.jpg

joints_fig2.jpg?sfvrsn=a4b232bf_2

 

 

A 20'x40' re-slab will probably take closer to a week.

 

It will also take a full truckload of concrete, so no short load charges.

 

 

Are you in a freeze/thaw zone?

 

- Adding fibers will help.

- Air Entrainment will help.

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13 hours ago, Blue Devil said:

 

Concrete... cracks. And hope doesn't do a damn thing.

 

8>)

 

- Stiff (< 4" slump, or 1 gal. water/Yd^3/ additional 1" slump)

- Rich (3K psi mix for foot, 4K psi mix for traffic)

- Reinforced (6x6/10x10 WW mesh w/ 3/8" perimeter rebar)

- Controlled

 

 

faq_joints_19166.jpg?sfvrsn=61b232bf_2

 

Feet/joint

joints_fig1b.jpg

joints_fig2.jpg?sfvrsn=a4b232bf_2

 

 

A 20'x40' re-slab will probably take closer to a week.

 

It will also take a full truckload of concrete, so no short load charges.

 

 

Are you in a freeze/thaw zone?

 

- Adding fibers will help.

- Air Entrainment will help.

No, not much of a freeze-thaw issue.  Definitely want cuts for controlled cracks.  No traffic or heavy objects will be on this slab.   So, what should I be looking at price-wise, boss?

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