WA0002-CS040818August 18, 2004
PK No.: 2269-02.022
Ms. Suzan Taylor
CITY OF COPPELL
255 Parkway Blvd.
Coppell, Texas 75019
Re:
GOLDEN TRIANGLE MOBILE HOME PARK - FIowable Fill
Coppel/, Texas
Dear Ms. Taylor:
If the City of Coppell takes no exception to using the minimum standards set by The
North Central Texas Council of Governments (N.C.T.C.O.G), we offer the following
specification options for flowable backfill:
2.1.5.(e) Flowable Backfill shall consist of a mixture of native soils or
manufactured materials, cement and/or fly ash, and water which produces a
material with unconfined compressive strength of between 250 and 450 psi after
28 days. Any materials used shall be primarily granular, with a plasticity index
<12 and with 100% passing a % in. sieve. The flowable mixture shall be mixed
in a pug mill, concrete mixer, or transit mixer and shall have a minimum slump of
5 in. The flowable mixture must be allowed to set prior to the placement of any
overlying material.
2.1.5.(f) Modified Flowable Backfill shall consist of a mixture of native soils or
manufactured materials, cement and/or fly ash, air entraining material, and water
which produces a material with unconfined compressive strength of between 50
and 150 psi after 28 days. Modified flowable backfill in permanent areas such as
abandoned pipe closures, abutments and embankments shall contain similar
materials and shall have an unconfined compressive strength of greater than
150 psi after 28 days. Any materials used shall be primarily granular, with a
plasticity index <12 and with 100% passing a ~ in. sieve. The flowable mixture
shall be mixed in a pug mill, concrete mixer, or transit mixer and shall have a
minimum slump of 5 in. The flowable mixture must be allowed to set prior to the
placement of any overlying material.
If you have any questions regarding the N.C.T.C.O.G standard specifications or need
any additional information, please call me at your convenience.
Sincerely?~_.~~ ',,
/// ~.j~.Chds~opher~¢i/.. JoneS, P.E.
CMJ/tw
2269-22
inc.