uhm- i meant neophyte. concrete tips for the neophyte.
pouring a 13 x 20 slab this friday and i can handle it- just always make too much work outa it.
so it is outdoors and confined so a truck and chutes are not gonna get close enuff. got a mud buggy and an old guy to handle the transport to the forms. (my dad loves it when i refer to him as an old guy)
six inches of crushed lime stone under w/vb cause eventually this will be indoors.
got the bull float, got the mag floats, got the trowels and edgers and knee boards and not remotely worried about finishing it out.
don’t know the first thing about additives and or water amounts to make it workable.
pouring at two – rain or shine cuz it is under roof.
this is just a four inch slab- no weight bearing- storage room floor
suggestions to ease the process?
thanks,
hub
Replies
Beer.
before during and after i presume?
i was gonna call my concrete man on account of favors he owes but the wife said save 'em for the driveway.
nother thought-
hey jeff buck- case of good beer and better steaks if you can be here by noon on friday!
some finish work required...
hub
hey jeff buck- case of good beer and better steaks if you can be here by noon on friday!
That High pitched noise you just heard is the sound of the tires on his new Jeep squealind when he took off!!Mr T
Happiness is a cold wet nose
GO ORANGEMEN!!!
To hubcap,
Where do you live?
What temperature does the forecast in your area call for?
Will there just be the two of you to pour the floor?
Pop The beer after the floor is troweled!
Pat.
i live in ohio. forecast is for clear skies, high temp of 32 and overnight low of 20. so i think i will pour at noon instead of two.
i can easily tarp the two open sides and heat overnight if necessary. or is visquene and straw enough? temps rise on saturday and stay above freezing into next week.
Hubcap,
SamT's concrete mixing recipe and tutorial;
Ideally you will get a 9" slump. This means that enough water has been added to the mixed to cause it to slump to 9" tall when a slump cone has been used. A slump cone stacks a truncated cone of fresh concrete mix 12" high. If more water has been added the cone will sag to less than 9", after a 6" cone there has been too much water added and cracks and poor finish are garunteed. If it slumps less than 1/4" (debatable) or not at all, you have drypack.
When you order standard slab concrete, your getting a 3000 to 3600 lb mix, this is also probably a 4-bag mix, that is, 4 ea 90lb bags of cement to 1 yd of aggregate (sand and gravel.) With enough water added to the mixer to give a 9" slump.
A 9" slumps works easy enough, finishes well, and has minimal cracks.
A 6" slump has about 2400 lbs compressive strength, works itself almost, takes longer to dry to finishing stage, and will probably crack.
Good drypack, that is, its slump cone will have zero slumping, some crumbs falling off, and most of the sharp upper edge left. It gets packed into position. With a 2x4 manually for a tile countertop or shower base, with a drift punch and hammer under steel columns, and with a rubber mallet, then scraped flush, for plugging snaptie holes before parging on formed concrete.
Drypack can't be finished with normal procedures, it is difficult to work, and never (ordinarily,) cracks. It will test out 5000lbs-6000lbs.
If you want to make any mix easier to work, without effecting finishing or strength, add "Slump Reducing Admix." You can safely add up to 3"-4" slump. It is expensive.
If you mix your own, add water slowly while stirring well, just until the mix "slicks" when you plow the back of your clean shovel thru it. To shadetree measure the slump, pile up the mud into one end of your pan or barrow, use the blade of your shovel to measure the depth, 9" if you can. With the shovel, Cut a section off and measure the slump height of the remainder. %75 slump = 9", %50 = 6".
If it's too wet, add a 1/2 shovel or so of cement, not sand. It will dry it out and make it stronger, sand will weaken the mix. You can alternate one cement/one sand, but start with cement.
To virtually prevent cracking, Use rebar and lay visqueen on it for a week after you finish.
SamT
thanks sam.
so straight off the truck should be workable?
hub.... sam's recipe is about the best i've seen in print..
his admixture he mentioned at the end would be what i'd want.. IE: reduce the mix water and add the "plasticizer"... you get the workability and slump without the additional water..
the extra water will affect it two ways ... more bleed water. delaying the finish.. and a weaker concrete.. with crazing on the finish..
just make sure it doesn't kick on youMike Smith Rhode Island : Design / Build / Repair / Restore
you need a five inch slump ( tell the driver five inch slump) and you need to place about 7:30 , 8:00 in the morning. It take couple hours on cool day to set. Get a long straight 2x4 as a screed board. after is poured, quit messing with it, bull float one time and leave it. that where dusting happens. after it set you can fix your mistakes. wear gloves and rubber boots.
A 5" slump?
Are you measuring how much it slumps or how high it is after it slumps.
There is a regional difference in the use of the term "slump". A 5" slump measuring how much it slumps is 7" high. Both are ok, if a little wet for my taste.
I think it is most prevalent to see how high it is after slumping. So a 7" slump is 7" high.
A 5" slump measuring how high it is after slumping is too wet for most use.
SamT
>>so straight off the truck should be workable?
Don't know. You have to tell the plant what slump you want when you order it. Sometimes, they will add just enough water on the way to your house to start mixing, (they don't want to over mix it,) and you tell the driver what slump you want at the site. It takes less than a minute to add water and mix it in.
In your shoes, I would tell them a 9" tall slump and let the driver or plant decide what was wet enough.
If the mud slides down the chute in clumps, add a little more water.
About the plasticer/slump-reducing admix, Mike Smith said "just make sure it doesn't kick on you." These types of admixes only work for about 30 mins after added to the mix. When they "kick" the slump reverts back to what it was before admix. If you haven't scree'd by then you're in a heap o' trouble. Since you haven't got a lot of experience pouring, I think you should stay with straight water. Just till after scree'ing, then you can mix a little JD with yer water.
SamT
thanks Sam. pretty sure i am on the same page with you.
let me recap sam,
i wanna order a nine inch slump (meaning when the cone is removed from a twelve inch tall truncated column of concrete it will sag and or spread and upon measure be nine inches tall or there abouts) and i don't want to go below a six inch slump on account of compromising the integrity of the concrete to extreme.
coming down the chute it should flow and not clump. clumping means add water and you said some and i guess that is where my question lies- how much is some?
like how many gallons per yard will amend my four bag mix by - what in terms of slump?
screw this slump stuff ...
just tell the yard ya want it sent thick and thinned on site ...
then ... if the truck driver is an old guy that can't bend at the waist from humping too much concrete ... tell him to make it as he see's fit.
I don't see any need to get messed up by any admixes ....
Work yer #### off ....
lay the plastic and throw some straw around ....
What's it for ... garage?
what ya planning for control joints?
You shoulda called .... I just told the guy helping me ... OK .. see ya Fri and maybe we'll put in a coupla on Sat before some beers ....
Timing ...
it's all about the timing.
It's been plenty long ago since the last concrete pour ...
and I've spent enough time indoors all winter ...
I'da jumped at the offer to play in the mud and drink some beers ....
I hate concrete ...
every now and then I gotta remind myself why I absolutely hated those 2 years I humped concrete and the only wood I touched was for forms ....
Oh yeah ... have the forms done ... and braced ... plenty early.
Like the day before ...
then check everything about 6 times before the first truck shows up.
JeffBuck Construction Pittsburgh,PA
Artistry in Carpentry
does this mean you are forsaking me? not gonna be here?
did i mention the beer and steaks?
gonna gravel and form tomorrow
hey there is gonna be dancing girls and maybe a giraffe and elephant- yew don't pretend to want to miss that do you?
I hate concrete too- don't mind finishing it once it is placed- getting it there sucks. (I love pumps)
brought straw home tonight visquene is in the trailer, rebar for grade stakes in the truck, got thirty thousand chairs left over from the last footer job and some various lengths of #5 rebar lying about and half a roll of tie wires
if i knew what i was doing this could be a first rate job...
control joints- saw 'em later- got leftover sill sealer for slab to wall
Edited 3/10/2004 9:50 pm ET by hubcap
You're expecting 32 high and 20F low? That will slow the set of the concrete by a fair bit. 50-55F is great for concrete - it gives you more time to get it placed and finished. But at or below freezing, you've got too much time if anything.
And what will the temp be in 2-3 days? You'll still be getting more strength at that time, until it dries out or freezes. You want to keep it from drying out or freezing as long as possible. I've spread 2" blue board on top to retain the heat of hydration that the curing concrete develops. Others use straw or old carpet. (Carpet's nice for retaining water). As soon as the finish is done on top, you want to be keeping it moist/wet.David Thomas Overlooking Cook Inlet in Kenai, Alaska
Hub,
You're getting too worried over this, See Jeffs reply and read it twice.
For more concrete info see some of the belows;
http://www.cement.org/basics/
http://www.marshalltowntrowel.com/howto.html
http://www.concretenetwork.com/
http://muextension.missouri.edu/xplor/agguides/agengin/g01700.htm
Slump:
Modified Slump Test to Measure Rheological Parameters of Fresh Concrete
The Slump Test
My thanks to BrownBagg and my apologies to all. I googled "slump test." In Calif. slump was the difference in the two heights, here I've ran into slump being the height of the slumped cone, IIRC, a web site on testing slump also gave the hieght of the slumped cone. Confused the heck out of me then, and now I've got the tedious task of removing all that bad info from my brain after I had just got it in there...if you knew my brain you would realize just how hard that is going to be.
Dam "Common Knowledge" anyway.
I will in the future remember that there is confusion in the world about which is correct and specify which way I mean. Unless I don't.
My bad.
SamT
"You're getting too worried over this,"
Really ... I mean ..... concrete .. we're talking hard grey dirt.
Where's the problem?
All the warm weather guys worrying about the temps are funny too .....
This is the rust belt ... dammit! We build outside year 'round .....
Jeff
Buck Construction Pittsburgh,PA
Artistry in Carpentry
I once worked for a company that poured a 6000yd monolithic footing in 125 degree heat. Bought out the full 24 hour production of two icehouses and two batch plants. Had engineers standing by the 2 boom pumps adding ice to the mix, checking thermocouples and timing the mixing with a stopwatch. Two shifts poured from 4am to 11pm.
I'm sure glad I was an electricians helper then.
SamT
"You're getting too worried over this,"
Really ... I mean ..... concrete .. we're talking hard grey dirt.
Where's the problem?
I love that quote, I,m going use it tomorrow, the finisher are going to catch hell.
Have at it!
I'm pretty good at coming up with stupid stuff that'll piss off most anyone else in the room .... luckily most all my subs have the same sense of humor.
JeffBuck Construction Pittsburgh,PA
Artistry in Carpentry
I have always heard (and seen) that the measure of slump was how much the concrete "slumped" when you remove the cone, not how much is still standing tall. I think there is an ASTM standard on how to measure. I'll see if I can locate it.
I been holding my tongue all day on this post. as most know, I is a concrete inspector. The slump is the different from top of cone to top of sample so a five inch slump is dryer than a nine inch slump. So I repeat as in my first post. Tell the driver you want a five and go with it. All this info is in the ACI manual
Cheap shot, luring us into this thread with promises of chia pets. Some people just have no scruples...
Hope all goes well on Friday.
"A completed home is a listed home."
i keep my scruples with my marbles and innocense...
so i can find them when i need
Well ......??
It's Fri nite ...
how'd we do?
Jeff
Buck Construction Pittsburgh,PA
Artistry in Carpentry
i think we're still doin.....Mike Smith Rhode Island : Design / Build / Repair / Restore
so we did fine and dandy. dad almost rolled the skidsteer and i thought how can you possibly be dumb enough to roll a bobcat why did i ask you to help how much does it cost to drag that pig outa the woods and how long has that mud been on the truck?
and then we poured all the crete and nobody died.
screed, bull, once over to knock it down.
tented and blowing heat... it is flat enuff to tile
that is good enuff fer me fetr now
Edited 3/12/2004 10:50 pm ET by hubcap
i will cover and straw in the am...
hey.. you!... you with your face down in the mashed potatoes ..
concrete days sure can get looonnnnggggg Mike Smith Rhode Island : Design / Build / Repair / Restore
it was hard enuff to walk on about two a.m. when i covered it.
time to scrape off these potatoes and go build cabinets.
feels like the day after is gonna be long...
I never said nothing about walking on it!
dammit ... the warrenty is voided!
Jeff
next thing ya know ... you'll be wanting to park stuff on it ........Buck Construction Pittsburgh,PA
Artistry in Carpentry