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PAGE 18 — MAYCO ST-45HRM CE PUMP — OPERATION & PARTS MANUAL — REV. #0 (02/23/04)
ST-45HRM CE CONCRETE PUMP— GENERAL INFORMATION
In addition, the Mayco Concrete ST-45HRM CE Pump can be
used to pump a large aggregate hard rock as follows:
1. Pea rock 12.7mm (1/2" minus) pump with mixes being as
low as 30% rock and 70% sand. (See page 50, for comments
on cleaning the pump.)
2. Shortening pea rock when used with an air compressor and
nozzle. (See back pages for recommended set-up.)
3. “Mud Jacking”, high pressure grouting.
Regional Differences
Concrete is made by mixing locally available rock and sand with
cement and water. For this reason there are great differences in
the pumpability of concrete from one region of the country to
another.
It is impossible to define a specific mix for each region that the
Model ST-45 be will working in. Therefore, the mixes on pages
64-65 will provide a basic guideline for establishing the proper
mix design for your area.
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:
227 Kg (500 lbs.) of cement/cu yd for 17.2 mPa (2500 p.s.i.)
concrete after 28 days.
240 kg (530 lbs.) of cement/cu yd for 20.7 mPa (3000 p.s.i.)
concrete after 28 days.
272 kg (600 lbs.) of cement/cu yd for 27.6 mPa (4000 p.s.i.)
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.