Different reco on driveway

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Old 09-16-16, 06:14 PM
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Different reco on driveway

I am in the process of redoing my front yard which will include new driveway.
I decided to go with a "mix" of concrete and concrete decorative stone - by mix I mean that borders and transitions will be stones lined up along the larger concrete slabs.

The question I have is that after several quotes - I got one guy that seems good but has different approach.
Unlike other masons, this one recommends only 2inch of base layer/stone and then 6inch of 2000lbs high pressure cement ?
No metal bars, no mesh or anything like that...which all others said must be put down so that the slabs don't crack.

Is this guy legit ?
 
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Old 09-17-16, 04:31 AM
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imo: most masons have neither the knowledge OR skill to properly place, finish, & joint concrete,,, 2" of base is inadequate as is 2,000# conc,,, for us, min is well-compacted granular base w/4" of 3,500# air-entrained conc,,, when we built roads in sc, paving over sand/clay was often spec'd,,, rebar/wire mesh is optional IF there's 2" of conc above AND below the steel/mesh,,, rarely is mesh at correct elevation (vertical midpoint of the conc +/- 5%) after the conc jabonies finish tramping thru the mud

the BEST method to control cracking (all conc cracks) is a proper joint pattern installed at the right time & to the recommended depth (thickness/3) + keeping heavier loads than d/w is anticipated to receive (rolling vehicles provide less stress than parked vehicles)

fiber is sometimes used in conc but it doesn't control random cracking,,, it DOES help fiber folks buy larger boats tho
 
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Old 09-17-16, 11:05 AM
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thanks - this is good info.
Is there some equation whereas you can equate thickness of the concrete to its psi value ?
i.e. you mentioned above that you'd be using 3500psi but at only 4 inch.... how would that compare to 6inch of 2000psi ?

Thanks!
 
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Old 09-18-16, 03:56 AM
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You have freeze/thaw winter conditions similar to Minnesota, correct? Please completely ignore that mason's talk about 2000 psi. In order to get resistance to freeze/thaw and deicing chemicals used on the roads, which is what you really want, you really should use a minimum of 4000 psi concrete that is air entrained. And if you really want a mix that'll add resistance to freeze/thaw and chemicals, request a 6 bag mix; it really won't add much cost. That means 6 bags cement per yard of concrete; that was our standard specification for exterior concrete in MN. Then, as stadry said, get a crew with experience in placing concrete.
 
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Old 09-19-16, 03:11 PM
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are you guys suggesting that masons are not familiar with placing concrete ?
What would be the professional who does this type of work called ? Not sure who to look for....
 

Last edited by PaulSC; 09-19-16 at 03:44 PM.
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Old 09-19-16, 03:33 PM
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Look for concrete contractors.

When the mason you talked to suggests 2000 psi concrete for exterior concrete, I think I would be safe in saying he is not familiar with placing concrete. Heck, I wouldn't even use that for interior concrete.
 
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Old 09-27-16, 04:25 PM
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So this is just for the record.....I completely misunderstood my mason.
I wanted to "probe" the idea of using 2000psi and he was like "What are you talking about ? I am using 4000psi.....I don't remember when I used 2000 last time....."

He showed me some of his other work in the area and seems really nice and solid....even the older constructions.
I guess 6inches of 4000psi for driveway should be good.
 
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Old 09-27-16, 06:47 PM
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Just using 4000 psi may not even be proper, depending on your climate.

Ideally, for winter freeze/thaw resistance for slabs both air entrained concrete AND 4000 psi compressive strength should be used the air entrainment is a minimal cost and it may even be in all concrete for driveways and streets. Around here, some concrete suppliers will not even deliver or dump a load of concrete that does not meet their criteria for air and strength. - The drivers have a waiver form for the contractor to sign.

Dick
 
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