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PAGE 26 — MAYCO C-30HDNI (PRECISION) PUMP — OPERATION AND PARTS MANUAL — REV. #7 (04/03/12)
C-30HDNI (PRECISION) PUMP — GENERAL INFORMATION
The following operating principles and operating suggestions
should prove helpful in the successful operation of your concrete
pump. Your new “small line” concrete pump has been designed
to give you many years of service when operated properly. A
study of the following paragraphs is important to the successful
operation of your new Direct-flow Concrete Placer.
All concrete pumps require a high level of operator skill and
more frequent service than most of the other construction
equipment. The highly abrasive nature of concrete under pressure
makes it extremely important that expendable wear components
be inspected at regular intervals between jobs to prevent having
to replace these items during a pour.
Experience has proved that inconsistency of batched concrete
mixes and frequent moving of the line requires the operator to be
readily available at all times during pumping to stop the pump
and prevent abuse to the unit which may occur if unexpected
blockages develop.
As a general rule, the use of approximately six sacks of cement,
70% washed concrete sand and 30% #4 pea gravel per yard of
concrete will result in a pumpable mix. The ideal nature of sand
and rock in certain areas may permit you to increase the
percentage of rock or adjust the mix considerably to meet the job
requirements. When possible, you may experiment with various
mixes in your area to determine the degree of versatility of the
Direct-flow Pump.
Uniform gradation of the washed concrete sand and the 1/2”
minus aggregate along with sufficient cement content and water
are important to a successful pump operation.
A recommended pumpable mix design would be 70% sand and
30% aggregate-cement content to be a minimum of 6 sacks.
(564 lbs.)
Sample Design Mix - 3000 Psi 3/8 in. Slump 4- 5 in.
Type II Cement 6.49 sack/cu. yd 611 lbs.
Sand Sat. Surf. Dry 2000 lbs.
#4 Gravel Sat. Surf. Dry 864 lbs.
#3 Gravel Sat. Surf. Dry 0 lbs.
Water 48 Gallons 400 lbs.
Total Weight 3,906 lbs
Admixture WRDA-79 26 oz.
Water 7.40 gal/sack
Test laboratory data has proven in many areas that the above
mix guidelines have produced concrete rated at 3000 psi (28
day test) and upwards of 5000 psi with an increase in cement.
In some areas where the gradation of sand and rock is ideal and
sufficient cement is used along with admixtures, the Mayco small
line concrete pump will handle up to a 50-50 ratio of sand and
rock.
When the mix is designed for wet gunning applications, it is
normal to increase the cement (up to 7.5 or 8 sacks) and change
the sand to rock ratio to 85% sand and 15% rock.
The Mayco concrete pump will valve efficiently when using
cellular-foam concrete mixes upwards of 70 lbs. per cubic foot
wet density. (Below 70 lbs. materials (roof decks) the valving
becomes inefficient.)
Your local sand and rock engineers
will give you the S.S.D. weights of
sand and rock required in your local
area which will yield one cubic yard
per the above recommendation.
If jamming conditions in the pump or
hose occur for any reason at all, do
not attempt to use more power to
correct the condition.
NOTE
NOTE
Determine the cause of jamming, correct it and resume pumping.
Trying to force material through under jammed conditions may
result in damage to the drive system, thus voiding any warranty
services.
Pump Mix Guidelines
When ordering concrete, be certain to advise the concrete supplier
that you require a “
pump mix
”. The Direct-flow manifold will
pump a wide variety of materials, but certain basic principles
must be followed to assure successful pumping, as follows:
Generally speaking, the washed concrete sand and #4 aggregate
(pea gravel) should conform to A.S.T.M. standards in regard to
sieve analysis. Sands in some areas are washed clean of the
#100 and #200 mesh fines, which results in separation and
jamming in the manifold while pumping under pressure.
If this condition develops, check with your concrete suppliers
engineers and get their recommendations for supplementing
the lack of the fines. The use of locally accepted ad-mixes may
be required. (For example, Pozzolith, Bentonite Clay, Plastiments,
etc.) When properly prescribed, additives form the plastic paste
sometimes necessary to hold the cement and aggregate together.