From: Laurence B. Oeth III <viacalx(--nospam--at)europa.com>
To: seaint(--nospam--at)seaint.org <seaint(--nospam--at)seaint.org>
Date: Sunday, June 27, 1999 9:32 PM
Subject: Re: Shotcrete Loading
>Hasan Hindawi wrote:
>> I've used guniting in several relatively small scale domes. The problem
>> that the procedure does not give you the specified concrete design
>> Therefore, samples should be taken and tested prior to guniting the
>> -----Original Message-----
>> From: Laurence B. Oeth III <viacalx(--nospam--at)europa.com>
>> To: seaint(--nospam--at)seaint.org <seaint(--nospam--at)seaint.org>
>> Date: Sunday, June 27, 1999 2:28 AM
>> Subject: Re: Shotcrete Loading
>> >Roger Turk wrote:
>> >> A. Yango,
>> >> Shotcrete = Pneumatically Placed Mortar (PPM) = Gunite (TM)
>> >> The method where mortar (concrete) is blown against earth/forms using
>> >> compressed air. The mortar can be a wet mix or a dry mix where the
>> >> inserted at the nozzle. Most commonly used in construction of
>> >> residential swimming pools and slope protection at bridge abutments.
>> >> A. Roger Turk, P.E.(Structural)
>> >> Tucson, Arizona
>> >> A. Yango wrote:
>> >> I just would like to ask what is shotcreting. We might have an
>> >> term for that here in PI. Thanks.
>> >NOTE: Shotcrete and gunnite are not the same. Shotcrete is a concrete
>> >mixture which is mixed and pumped and sprayed out the nozzle. With
>> >gunnite, water and cementitious materials are mixed at the nozzle.
>> >(...or did I get those two reversed? Never can remember) Anyway, both
>> >have advantages and disadvantes and are sensitive to the experience of
>> >the applicator. Perhaps more for the gunnite.
>> >Laurence B. Oeth, P.E.
>What design strength were you specifying? Did the applicator have a
>track record of achieving your specified strength on other jobs?
>It can be done, but shotcrete and gunnite for structural purposes is
>definitely a specialty and needs to be approached that way in design.
>Laurence Oeth, P.E.
>The original design was not based on guniting. Therfore, the specified
design was 4000psi. But the contractor convinced the client that he could
finish the job faster using the above approach. We requested tests prior to
the original casting regardless of his track record because, I am talking
about a job in the United Arab Emirates. It is located on the Persian Gulf,
where the tempertaures reach 115f during the day. He only acheived 2800psi.
We had to redesign the domes.