several thousand feet deep. The concrete segregates during the fall and 
is usually remixed at the bottom before being placed. This method is 
not applicable to underwater placement. 
Slurry Transport. Particulate matter such as coal is transported 
long distances in “slurry pipelines." Similarly, spoil from hydraulic 
dredges and many materials in processing plants are transported in 
pipelines by two-phase flow with the suspended solid particles propelled 
by the drag forces of the faster moving water or other fluid. Usually 
turbulent flow is maintained to prevent particles from settling out. 
This technology is not applicable to pipeline transport of concrete. 
SYSTEM DESCRIPTION 
Overall Configuration 
A representative arrangement for a deep ocean concreting operation 
is shown in Figure 2. The surface platform is positioned at the site 
with the pipeline deployed for concrete encasement of objects on the 
seafloor. The pipe handling mast is located amidships over a center 
well. Pipe is stored horizontally on the deck. The concrete batch 
plant, mixer and pump and the concrete materials storage bins are located 
on one or more decks; for large jobs additional materials storage would 
be on a barge alongside. 
Concreting System 
The components of the concreting system are shown schematically in 
Figures 3 and 4. The materials storage, conveying and batching equipment, 
and the concrete mixer and pump are conventional concreting equipment. 
The pipeline consists of standard oilwell tubular goods. The pressure 
equalizer, the concreting head, and the seafloor discharge device are 
not off-the-shelf items and are specifically built for deep ocean con- 
creting operations. 
Materials Storage and Handling. The concreting materials are the 
cement, sand and gravel aggregates, water and admixtures. A typical 
concrete for use in the ocean weighs about 150 pounds per cubic foot or 
2 tons per cubic yard. The aggregates make up more than 75 percent of 
this weight, the cement about 16 percent, water about 8 percent, and the 
admixtures a fraction of a percent. The bulk weight of the stored 
aggregates is roughly 100 pounds per cubic foot and of cement 75 pounds 
per cubic foot (aerated bulk density after being conveyed pneumatically) 
so that about 4,600 cubic feet of storage volume are required for each 
100 cubic yards of concrete to be placed. Weight and volume storage 
requirements for materials to produce various quantities of concrete are 
shown in Table 1. 
Industry has developed bulk materials storage and handling methods 
including portable and relocatable systems for temporary applications 
that are suitable for barge or shipboard use. 
