When time came to pour the base for my self-supporting HDX-555 several years
ago, an argument erupted with the concrete truck driver when he delivered
"soupy" mix that failed the "slump test" specified by US Tower.
I had hired out the digging of the base hole and the construction of the rebar
cage. My contractor hadn't worked on a tower project before but had done other
excellent work for me. He was scrupulous in studying the engineering specs and
following the manufacturer's instructions. I overheard him ordering the
concrete and being very specific about the required consistency. When it
arrived "soupy" and the driver scoffed at his objections, my contractor called
the concrete company manager, reminded him of the details of the order and said
we were rejecting this delivery. The manager wasn't thrilled but he agreed. The
pour was delayed a day but, as someone who knows only a little about
construction materials, I was grateful that my contractor rejected the driver's
insistence that "concrete is concrete" and had insisted upon following the
manufacturer's recommendations.
Does your tower manufacturer's instructions mention a "slump test"?
73,
Mike K0MYW
On Tuesday, October 21, 2014 9:00 PM, "john@kk9a.com" <john@kk9a.com> wrote:
One concern is if you are making the concrete "soupy" by adding extra water
it becomes less strong. A 30' aluminum tower has a small concrete base so
why not play it safe and use the proper mixture?
John KK9A
To: "towertalk@contesting.com" <towertalk@contesting.com>
Subject: [TowerTalk] Using old concrete in new pour
From: David Gallatin via TowerTalk <towertalk@contesting.com>
Reply-to: David Gallatin <kc9eev@yahoo.com>
Date: Tue, 21 Oct 2014 16:53:26 -0700
List-post: <towertalk@contesting.com">mailto:towertalk@contesting.com>
Hello everyone,
A ham friend today suggested using concrete from an old pad that's broken
into
small (maybe fist size or a bit smaller) pieces and using it in
a new pour, specifically for my new 30 foot aluminum tower. He said you make
the new mix "a little soupy" and toss the old chunks in as you go, the idea
being less new concrete is used (and paid for) and when it dries you can't
tell
a difference "concrete being concrete". He did not specify what kind of
ratio
of old to new is used but he does have two pads of his own he has done this
with that hold 60' steel self supporting towers.
I have tried to research this and come up with nothing. I did find reference
to
concrete being recycled (crushed) into aggregate size and used as such in
new
pours but what he is talking about does not seem to be the same thing.
Obviously I am a tad concerned about doing this. Has anyone heard of this
technique before?
73,
David, AA9G
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