concrete base question

[LocutusOfBorg]

What makes redi-mix or "mix it yourself" better than quickrete? Aren't they all made up in the same proportion of sand/cement?

 

[phlatwound]

What makes redi-mix or "mix it yourself" better than quickrete? Aren't they all made up in the same proportion of sand/cement?

You have it figured out.....the quality is determined by the proportions of cement, sand, aggregate(s), admixtures and water. But not all mixes are equal, you can order basically whatever proportions (within reason) you want from a ready-mix company.

A typical footing/foundation mix around here is specced @ 3000 psi, and usually contains about 5 "sacks" of cement/cubic yard. I don't know if they advertise (put it on the bag) a compressive strength on Quikrete.

It doesn't matter if it is delivered by a ready mix truck, or a wheelbarrow.

 

[rodder]

Quikrete is only 1500 psi. when i use it i buy a bag of cement and add about 3 or 4 shovels to each bag of Quikrete.

 

[truckracer]

I just used quickrete. it has been fine over the years.

 

[LocutusOfBorg]

You have it figured out.....the quality is determined by the proportions of cement, sand, aggregate(s), admixtures and water. But not all mixes are equal, you can order basically whatever proportions (within reason) you want from a ready-mix company.

A typical footing/foundation mix around here is specced @ 3000 psi, and usually contains about 5 "sacks" of cement/cubic yard. I don't know if they advertise (put it on the bag) a compressive strength on Quikrete.

It doesn't matter if it is delivered by a ready mix truck, or a wheelbarrow.

I just got back from my local Home Depot and they have Quickrete sacks labeled 4000 PSI. I guess that should get the job done?

 

[Lone Cloud]

I just got back from my local Home Depot and they have Quickrete sacks labeled 4000 PSI. I guess that should get the job done?

Just read the thread. Where are you located? I bought some j bolts a while back for a home improvement project and I had some left over. If you are close enough, I'd give you 3 of them. I'm in SoCal

 

[LocutusOfBorg]

Just read the thread. Where are you located? I bought some j bolts a while back for a home improvement project and I had some left over. If you are close enough, I'd give you 3 of them. I'm in SoCal

I'm in Nebraska. I have the bolts anyway.

Anyway, it turns out that Home Depot has commercial grade Quickrete rated at 5000 PSI, also. Probably overkill but I'll pay the extra buck per bag.

 

[toucan-man]

I just got back from my local Home Depot and they have Quickrete sacks labeled 4000 PSI. I guess that should get the job done?

Exactly. The bags here say 4000 PSI. I think Quickrete bashing is either undeserved or we're both missing something.

 

[phlatwound]

My SWAGmeter tells me that 100% of my sat poles and approximately 87.2% of all BUD poles in the USA have been set using Quikrete, with a failure rate 0.000072%.

Git er done.

 

[bmcglynn]

Installation of C-Band on Solid Bedrock

Hello,

I'm facing two challenges setting up a 12' BUD on our new property.

Challenge 1: We Face North.
Challenge 2: You can dig 2" to 12" deep before hitting solid bedrock (The Canadian Shield)

To come around both challenges, I can place the dish at the beginning of the property with 10' of elevation to clearly sweep 61W - 135W. (Already tested with a 36" KU band).

My plan is to strip away the small amount of dirt in a 5' x 5' section at the end of the property and build-up a base for the BUD. I would weld 36" support bars in a star formation around the base of a pole, and then encase it in 12" of concrete.

My question to the group is: How much concrete should I use as an anchor?

We will be above the frost line, although I would imagine that by putting the concrete on solid bedrock, shifting should not be an issue.

Any suggestions?

Thanks.
Brian - Ottawa, Canada

 

[Lone Cloud]

Hello,

I'm facing two challenges setting up a 12' BUD on our new property.

Challenge 1: We Face North.
Challenge 2: You can dig 2" to 12" deep before hitting solid bedrock (The Canadian Shield)

To come around both challenges, I can place the dish at the beginning of the property with 10' of elevation to clearly sweep 61W - 135W. (Already tested with a 36" KU band).

My plan is to strip away the small amount of dirt in a 5' x 5' section at the end of the property and build-up a base for the BUD. I would weld 36" support bars in a star formation around the base of a pole, and then encase it in 12" of concrete.

My question to the group is: How much concrete should I use as an anchor?

We will be above the frost line, although I would imagine that by putting the concrete on solid bedrock, shifting should not be an issue.

Any suggestions?

Thanks.
Brian - Ottawa, Canada

As someone who has mixed about a thousand bags of cement for a variety of home improvement projects, I would first make sure you add a good shovelful of portland cement to the mix. The bag mixes are better now, but you really can't be sure.

Secondly, when you say bedrock, what does that mean? Is it a flat, monolithic table of stone that the footing will have to sit on top of? Or is it boulders, which you can dig out in between and incorporate your concrete?

If it's separated boulders, I'd probably get some lengths of rebar and stick them down in between the boulders and then pour the mix in there.

If it's a table kind of rock, I'd consider getting a roto hammer to drill some holes in it and set the rebars in the holes

If you have essentially a big block of concrete sitting on top of the ground, with no reinforcement from the ground or the rock below, It's going to have to be a pretty big block. If it's a mesh 12 foot dish then the concrete can be smaller. but if it's a solid dish, yikes!

 

[vfrjim]

don't forget if you set the rebar into the rock, use an injection epoxy to set them in to it.


IMO though, I did not mix my own concrete, I had a truck come out and mix on site. He set it to just over a 5000 lb mix, best $230 I spent IMO, a very consistent mix that you can trust.

 

[LocutusOfBorg]

RediMix concrete will be poured this week since I can't find someone willing to mix 15+ bags of quickrete and I'm too lazy to do it myself. Anyway, someone mentioned that something should be done to get any trapped air out of the concrete - I'm not sure if that's necessary but I'm not a concrete expert. I've never worried about that issue before.

 

[phlatwound]

Unless you pour the concrete too dry you shouldn't have any issues with trapped air. Just pour it slowly and jab it a little with a board or piece of rebar as the hole is filling.

The concrete should run readily down the chute, if it doesn't it's probably too dry. It's easy to add water to your mix....and real hard to take it out. A 6" slump would probably be about right.

If you are pouring a cap on top and have some forms set above ground you should tap them with a hammer to get the air out that is against the form boards.

If the truck is made for pouring pavement you might even want to pour it into a wheelbarrow and then put it in the hole, it's hard to pour slowly out of a paving rig. A good driver helps, also.

And don't forget to check your pole for plumb after you pour it, even if you have it well-braced it can move when you pour it.

Also you should have some sort of tab on the pole in the concrete to keep it from turning in the wind.

 

[LocutusOfBorg]

Unless you pour the concrete too dry you shouldn't have any issues with trapped air. Just pour it slowly and jab it a little with a board or piece of rebar as the hole is filling.

The concrete should run readily down the chute, if it doesn't it's probably too dry. It's easy to add water to your mix....and real hard to take it out. A 6" slump would probably be about right.

If you are pouring a cap on top and have some forms set above ground you should tap them with a hammer to get the air out that is against the form boards.

If the truck is made for pouring pavement you might even want to pour it into a wheelbarrow and then put it in the hole, it's hard to pour slowly out of a paving rig. A good driver helps, also.

And don't forget to check your pole for plumb after you pour it, even if you have it well-braced it can move when you pour it.

I'm not using forms but I am using wood to support the pole. The pole isn't being set in the concrete because the type of pole I've been using, since I started with the BUD over 10 years ago, has a base welded to the bottom with 3 - 3/4" holes for L bolts. The L bolts are made of galvanized steel that are 42" long and are threaded which allows me to re-level the pole when necessary. This type of pole has served me well. My neighbor and his son are going to wheel barrel the concrete to the hole since it would be impossible to get the cement truck into my back yard without taking down the fence and without destroying the lawn. I'm too lazy to wheel barrel the stuff myself - I get enough physical activity at work and I make enough money to pay someone to do this for me. Anyway, adding more water, if necessary, isn't a big deal except that it will take the concrete a lot longer to cure (of course, I'm not an expert at concrete). Too bad I had to wait so long for the L bolts to be made - I would have preferred to have poured the concrete in warmer weather. I guess I'll just have to put some insulation over the concrete since it's suppose to get below freezing over the next week.

 

[phlatwound]

Oops, forgot about the anchor bolts and not pouring the pole in. You will be fine if you cover the top of your pour, as most of it will be down in the ground and safe from freezing.

The first night the concrete is putting off so much heat from the chemical reaction it would have to be a ways below freezing to hurt it, but still a good idea to cover it...the second and third days are when it's most susceptible to freezing, as the reaction slows. After a week or so you won't have to worry about the freezing deal.

 

[LocutusOfBorg]

concrete with fiberglass

The Ready Mix is being delivered this afternoon. In case anyone's interested, I'm having fiberglass mixed in with the concrete which I've been told is much better than using rebar for strengthening the concrete.

 

[LocutusOfBorg]

The concrete was poured yesterday - it didn't take as much concrete as I had expected - definitely less than a yard. In a couple of weeks I'll assemble the reflector and go though the "fun" of mounting and aligning.