systems would be needed for the forms, the aggregate and the grout. The 
method would be limited to applications using forms or other confined 
space. 
Large quantities of grout, on the order of 10,000 cu yd, have been 
placed under offshore gravity-type structures located in water depths to 
450 feet. The purpose is to provide uniform bearing on the seafloor and 
to minimize settlement, especially differential settlement. Grouts used 
for this purpose develop low strengths and are placed in confined chambers. 
Probably the largest deep placement operation was one in which more 
than 1,300,000 cu yd of 3/8-in. maximum size aggregate mortar were 
pumped downward about 1,000 feet into a large water-filled cavity under 
a dam (Ref 8). The purpose was to fill the enclosed void. Structural 
grade concrete was not required. 
Cementing Oil Wells. Sophisticated above-ground and down-hole 
equipment, materials and procedures have been developed to cement oil 
wells to depths of 20,000 feet or more under conditions of high pressure 
and high temperature (Ref 11). Practices are limited to placing cement 
slurries in confined holes using the back pressure of the drilling fluid 
to control flow. Concrete is not used. Cement slurries are typically 
water, cement and various specialized admixtures. For certain purposes, 
such as increasing the unit weight of the grout, fine sand is sometimes 
used. The maximum sand grain size that can be accommodated by pumps and 
downhole equipment is about 1/8 in. diameter. Sand, when used, is 
typically smaller than no. 20 size; i.e., about 1/30-in. in diameter. 
Well cementing methods have been adapted to some offshore platform 
construction: grouting platform pin-piles to the seafloor and grouting- 
in anchor piles. On one occasion a number of bell-bottomed reinforced 
concrete piles of 3-1/2-ft diameter belled out to 9- to 15-ft diameter 
at the bottom end were constructed in a total depth of about 500 feet. 
A grout with maximum sand size of 1/30 of an inch was pumped into a 
drilled hole (which contained the steel reinforcing cage) to displace a 
weighted mud slurry. 
Combined theoretical and empirical methods are used to predict the 
flow behavior in a pipeline of cement slurry treated as a non-Newtonian 
fluid. Flow calculations utilize experimentally determined coefficients 
related to slurry viscosity in laminar flow. This method is not directly 
applicable to plug flow of concrete in a pipe. 
The major aspect of construction grouting and oil well cementing 
technology that is adaptable to deep ocean concrete placement is the 
control of material properties, particularly prevention of water loss 
from grouts and slurries under high pressures and pressure differentials. 
These properties are controlled primarily by careful selection of mater- 
ials, control of mix proportions, control of procedures and use of 
specialized admixtures. Pumps and other equipment for grouting and 
cementing are not adaptable for concreting. 
Mine Construction. Concrete for shaft and tunnel lining and other 
underground construction has been transported to the deep depths by 
dropping the freshly mixed concrete down long vertical pipes. Copper 
mines in the U.S. and gold mines in South Africa have shafts that are 
