MAYCO LS450 CONCRETE PUMP • OPERATION MANUAL — REV. #2 (02/23/21) — PAGE 15
Use this information to specify your requirements to your
local ready-mix batch plant, contractor, and civil engineer.
It may take minor adjustments to make a mix pumpable,
so you should explain your needs.
The elements that have to be controlled and consistently
maintained by the batch plant are:
1. The sizing and mix percentage of rocks, gap-graded
from the largest down through the smallest sizes.
2. Sand with a sieve analysis that has the proper
percentage of fines, ASTM C33 spec.
3. Sufficient cement to produce the required design
strength of the concrete and provide the lubricating
binder to pump the concrete through the delivery system.
Use a minimum of:
500 pounds of cement per cubic yard for 2,500 psi
concrete after 28 days.
530 pounds of cement per cubic yard for 3,000 psi
concrete after 28 days.
600 pounds of cement per cubic yard for 4,000 psi
concrete after 28 days.
4. Admixture pump-aid if necessary.
5. The proper amount of water to make a workable slump
and plasticize the mix.
In addition, this Mayco concrete pump can be used to pump
a large aggregate hard rock as follows:
Pea rock (1/2" minus) pump with mixes being as low as
30% rock and 70% sand. (Refer to the Maintenance
section for recommendations on cleaning the pump.)
Shortening pea rock when used with an air compressor
and nozzle.
“Mud jacking,” high pressure grouting.
GENERAL INFORMATION
PUMPING INFORMATION
Remixtures
Remixtures that are designed into the concrete mix by
the ready-mix company or an architectural engineering
company. This section lists common admixtures and a brief
explanation of their functions:
1. Pozzolith 300 (or equivalent) — Acts as a water
retarder and a lubricant. On a lean mix, long pushes,
stiff mixes, and vertical pushes, Pozzolith 300R helps
pumpability.
2. MBVR — Air entraining, acts as a lubricant.
3. Calcium Chloride — Commonly referred to as ‘C.C.’,
is used as an accelerator. When pumping a load with
calcium chloride, it is recommended that you wash out
if the waiting time between delivery trucks becomes
too long.
4. Super Plasticizers — Acts as an accelerator. The
concrete will look very wet after the super plasticizer
is added, but will begin to set up very fast. Wash out
immediately if you do not have a truck waiting. Super
plasticizers are used mainly on commercial jobs.
5. Red Label — Acts as a water retarder and an
accelerator. Red label will be used mainly on
commercial jobs.
6. Fly Ash — Is used to help increase the strength of the
concrete and decrease the cement content per yard.
This is one of the most common admixtures used.
Downhill Pumping
Downhill pumping can be a difficult procedure on some
jobs. The slurry procedure would be the same as explained
in the Priming the Pump with Slurry Mixture section of
this manual. It is suggested that a sponge approximately
2" × 4" × 6" in size be placed in the hose before the start
of pumping.
NOTICE
All admixtures will be shown on the ready-mix concrete
ticket. Before starting the pumping job, ask the driver
of the ready-mix truck to see the concrete ticket. Note
the admixtures that exist and take the proper action.
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