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ACI 304.2R Document Information:
Title
Placing Concrete by Pumping Methods
American Concrete Institute
Publication Date:
Jan 1, 1996
Scope:
INTRODUCTION
ACI defines pumped concrete as concrete that is transported
through hose or pipe by means of a pump. Pumping concrete through
metal pipelines by piston pumps was introduced in the United States
in Milwaukee in 1933. This concrete pump used mechanical linkages
to operate the pump and usually pumped through pipelines 6 in. or
larger in diameter.
Many new developments have since been made in the concrete
pumping field. These include new and improved pumps, truck-mounted
and stationary placing booms, and pipeline and hose that withstand
higher pumping pressures. As a result of these innovations,
concrete placement by pumps has become one of the most widely used
practices of the construction industry.
Pumping may be used for most concrete construction, but is
especially useful where space for construction equipment is
limited. Concrete pumping frees hoists and cranes to deliver the
other materials of construction concurrently with concrete placing.
Also, other crafts can work unhampered by concrete operations.
A steady supply of pumpable concrete is necessary for
satisfactory pumping.1 A pumpable concrete, like
conventional concrete, requires good quality control, i.e.,
uniform, properly graded aggregate, materials uniformly batched and
mixed thoroughly.2 Concrete pumps are available with
maximum output capacities ranging from 15 to 250
yd3/hr.
Maximum volume output and maximum pressure on the concrete
cannot be achieved simultaneously from most concrete pumps because
this combination requires too much power. Each foot of vertical
rise reduces the horizontal pumping distance about 3 to 4 ft
because three to four times more pressure is required per foot of
vertical rise than is necessary per foot of horizontal
movement.
Pumped concrete moves as a cylinder riding on a thin lubricant
film of grout or mortar on the inside diameter of the
pipeline.3-5 Before pumping begins, the pipeline
interior diameter should be coated with grout. Depending on the
nature of material used, this initial pipeline coating mixture may
or may not be used in the concrete placement. Once concrete flow
through the pipeline is established, the lubrication will be
maintained as long as pumping continues with a properly
proportioned and consistent mixture.
Keywords:
- admixtures
- aggregate gradation
- aggregates
- cement content
- coarse aggregates
- concrete construction
- concretes
- conveying
- couplings
- fine aggregates
- fineness modulus
- lightweight aggregate concrete
- lightweight aggregates
- mix proportioning
- pipeline
- placing
- placing boom
- pozzolans
- pumped concrete
- pumps
- quality control
- water content
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