Thanks for all the great info! - Don N3MK
-----Original Message-----
From: towertalk-bounces@contesting.com
[mailto:towertalk-bounces@contesting.com] On Behalf Of Pat Thurman
Sent: Saturday, March 13, 2010 3:04 AM
To: Tower and HF antenna construction topics.
Subject: Re: [TowerTalk] Mixing concrete for a base
Good point Perry! Being from the desert, I didn't know that the area was
salt water... Definitely need to consider that in the mix design and
placement...
73, Pat K7KR
----- Original Message -----
From: "Perry - K4PWO" <k4pwo@comcast.net>
To: "'Tower and HF antenna construction topics.'" <towertalk@contesting.com>
Sent: Saturday, March 13, 2010 0:28
Subject: Re: [TowerTalk] Mixing concrete for a base
> There's under water and under salt water... in his case (Chincoteague
> Island) he's dealing with salt water. I recall that you need a special
> mix
> for that situation.
>>From site
>
http://www.epcserver.com/Structural/analysis/concrete/info_concrete_saltwate
> r.asp
>
> "Concrete in sea water should be impervious to protect the reinforcing
> steel.
> Mixing water shall not exceed 5 1/2 gal per sack of Portland cement.
> The mix should contain at least 7 sacks of cement per cubic yard of
> concrete.
> Entrained air should be between 3 and 6 percent.
> Aggregates should be verified not to be affected by sea water.
> Aggregate size should be limited to less than 1/6 the smallest dimension
> of
> the member and never larger than 1 1/2 inches.
> Exceptions to the 1 1/2 inch aggregate size may be made for mass
> placements.
>
> 3 inches of cover should be provided for reinforcing and 4 inches should
> be
> provided at corners.
> Metal reinforcement chairs should not extend to the surface and if
> possible
> should not be used.
> Form ties should provide deep recesses with extra care provided when
> patching.
> All attempts should be made to place concrete in a continuous operation.
> When construction joints are required, the placement shall be allowed to
> set
> prior to a new placement. The bonding surface shall be blasted with a jet
> of
> water and sand. Broom cement grout onto the cleaned surface and make the
> new
> placement immediately.
> High frequency vibrators should be used.
> Curing is important to establish a watertight paste. The concrete should
> be
> kept wet for 10 days at a temperature above 50o F."
>
> -----Original Message-----
> From: towertalk-bounces@contesting.com
> [mailto:towertalk-bounces@contesting.com] On Behalf Of Pat Thurman
> Sent: Saturday, March 13, 2010 12:56 AM
> To: Tower and HF antenna construction topics.
> Subject: Re: [TowerTalk] Mixing concrete for a base
>
> Google "Tremie method"... It is common to pour concrete underwater via a
> tremie chute for a variety of projects in water. The key is to keep the
> concrete undisturbed while pouring so the water-cement ratio of the mix
> remains as designed. Water curing is good.
>
> 73, Pat K7KR
>
> ----- Original Message -----
> From: "Don Snider" <dsnider@rhrs.com>
> To: "'Tower and HF antenna construction topics.'"
> <towertalk@contesting.com>
> Sent: Friday, March 12, 2010 20:06
> Subject: Re: [TowerTalk] Mixing concrete for a base
>
>
>> How about the quick-dry concrete used for fence posts? Can this be used
>> for
>> towers? My hamshack is on Chincoteague island with a water table about 18
>> inches down. Most people use the quick dry concrete for general projects
>> because it will dry in the water but is it strong enough for an antenna
>> base? The only other option may be to put well taps in and pump the water
>> our while the concrete drys.
>>
>> Thoughts?
>>
>> Don
>> N3MK
>>
>> -----Original Message-----
>> From: towertalk-bounces@contesting.com
>> [mailto:towertalk-bounces@contesting.com] On Behalf Of Mike
>> Sent: Thursday, March 11, 2010 11:18 PM
>> To: 'Tower and HF antenna construction topics.'
>> Subject: Re: [TowerTalk] Mixing concrete for a base
>>
>> Most cement/concrete guys are in terrible shape at the moment, they will
>> be
>> happy to deliver minimum 3 yards. They will make delivery charge, so try
>> and pick a company close to you. Concrete pump people do not charge
>> transport here anyway.
>>
>> Telephone a few different companies and tell each one that you have
>> phoned
>> around for quotes and you may be surprised what they will do.
>>
>> Even in California here I had 3 yards delivered and I had a concrete pump
>> guy to pump the concrete into the hole. The cost was around $900.00
>> total
>> for pump, Concrete and delivery. I can tell you the pump guy earned his
>> 260
>> bucks with 30 minutes preparation and 30 minutes clean up time plus 15
>> minutes to pump the concrete 50 yards. If you do use a concrete pump you
>> have to let the concrete people know so that they can use smaller round
>> stones.
>>
>> Usually if you have the concrete delivered they will wait about an hour
>> or
>> less (ask them for their waiting time) while you wheelbarrow it to the
>> hole
>> and charge waiting time which is expensive after that time. For some
>> reason
>> if you use a concrete pump they will stick around for as long as it takes
>> with no extra charge, maybe it is because the concrete delivery guy does
>> not
>> have to do much work when you pump concrete. With wheelbarrows he has to
>> keep opening and shutting the valve for an hour.
>>
>> If you have concrete left over use it to make something like concrete
>> weights. Put it in plastic buckets that pool tablets come in and make a
>> "U
>> shape" out of left over re-bar to make a hook and put into the center of
>> the
>> concrete filled bucket. When it is "set", a couple of them make a great
>> cheap counter weight for a tilt over tower like a LM-470.
>>
>> Mike, K6BR
>>
>>
>>
>> -----Original Message-----
>>
>> There is such a thing as a false economy - but I think
>> it would be difficult to finish 2.5 yards by hand, in a
>> timely manner. Such a pour should be done in one shot,
>> that is going to be tough.
>>
>> If you have any value on your time, adding the cost of
>> materials, etc, you quickly cost more than the price of
>> redi-mix.
>>
>> Although some places have a 5 yard minimum, most of
>> those will deliver 2.5 yards, with a extra delivery charge. Most
>> of the places I have bought concrete in the past 6 months,
>> NY, PA, OH, MO, and OK, have been right around 75 bucks
>> a yard, plus a delivery charge for under 4-6 yards.
>>
>> Cheaper to call them for me!
>>
>>
>> Don't take your organs to heaven,
>> heaven knows we need them down here!
>> Be an organ donor, sign your donor card today.
>>
>> ----- Original Message -----
>> From: "Ed Swiderski, KU4BP" <ku4bp@triad.rr.com>
>> To: "'Tower and HF antenna construction topics.'"
>> <towertalk@contesting.com>
>> Sent: Thursday, March 11, 2010 6:38 PM
>> Subject: Re: [TowerTalk] Mixing concrete for a base
>>
>>
>>>
>>> No, don't like pain. Just trying to it right with the least amount of
>>> money.
>>>
>>> Ed
>>>
>>> -----Original Message-----
>>> From: towertalk-bounces@contesting.com
>>> [mailto:towertalk-bounces@contesting.com] On Behalf Of Blake Bowers
>>> Sent: Thursday, March 11, 2010 7:17 PM
>>> To: Tower and HF antenna construction topics.
>>> Subject: Re: [TowerTalk] Mixing concrete for a base
>>>
>>> 6 bags of cement, 8 cubic feet of sand, and 20 cubic feet of gravel
>>> makes
>>> on
>>> square yard of concrete - using the 1, 2, 3 measuring.
>>>
>>> It also makes for a terrible day.
>>>
>>> Do you just like pain? I cannot imagine mixing 2.5 yards, I would use
>>> the
>>> local redi mix plant.
>>>
>>>
>>> Don't take your organs to heaven,
>>> heaven knows we need them down here!
>>> Be an organ donor, sign your donor card today.
>>>
>>> ----- Original Message -----
>>> From: "Ed Swiderski, KU4BP" <ku4bp@triad.rr.com>
>>> To: "Tower Talk" <towertalk@contesting.com>
>>> Sent: Thursday, March 11, 2010 5:57 PM
>>> Subject: [TowerTalk] Mixing concrete for a base
>>>
>>>
>>>>
>>>> All,
>>>>
>>>> I'm considering mixing my own concrete for my installation. Been trying
>>>> to
>>>> get a grasp on how much cement, gravel and sand to get. My proposed
>>>> base
>>>> is
>>>> for 70ft of 25G. Total, with the anchors, is 2.2 cu yds. Call it 2.5
>>>> since
>>>
>>>> I
>>>> plan to "bell" the base.
>>>>
>>>> I was pricing the ingredients today but got a little confused on the
>>>> amount
>>>> of each needed. I looked at 94 lb bags of cement and 50 lb bags for
>>>> both
>>>> the
>>>> sand and gravel. The problem I had was determining how much in cu yds a
>>>> bag
>>>> would cover. I have seen that a 50 lb bag of sand covers .5 cu yd.
>>>>
>>>> So what I'm looking for is a formula of some sort so I can figure out
>>>> how
>>>> much I will need of each. I've heard of the "1-2-3 rule" but not 100%
>>>> sure
>>>> I'm using it correctly.
>>>>
>>>>
>>>> Ed KU4BP
>>>>
>>>>
>>>> _______________________________________________
>>>>
>>>>
>>>>
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>>>
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