Multiquip ST70 - Manual (Page 13)

ST-70 — PARTS & OPERATION MANUAL — REV. #4 (05/29/07) — PAGE 13
ST-70 — GENERAL INFORMATION
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-70 be will working in. Therefore, the mixes on pages
14 through 17 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:
500 lbs. of cement/cu yd for 2500 p.s.i. concrete
after 28 days.
530 lbs. of cement/cu yd for 3000 p.s.i. concrete
after 28 days.
600 lbs. of cement/cu yd for 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.
In addition, the Mayco Structural Concrete ST-70 Pump can be
used to pump a large aggregate hard rock as follows:
1. Pea rock (1/2" minus) pump with mixes being as low as
30% rock and 70% sand. (See page 30, 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.