One of the frameworks was outfitted with rope, buoy, and acoustical 
release. The acoustical release could be actuated from the surface so 
that the buoy would bring one end of the rope to the surface. This 
framework could be retrieved when desired. The second framework had no 
ropes attached so that a manned submersible could approach without 
concern of entanglement. 
Low- and high-strength concretes were tested. The effects of the 
deep ocean environment could be different on either low- or high-strength 
concretes as a result of the different pore size distribution that 
develops within the concretes. Applications for freshly mixed concrete 
on the seafloor include: (a) for low-strength concrete, seafloor stabili- 
zation and object encapsulation; (b) for high-strength concrete, in-situ 
construction of pressure-resistant structures. 
CONCRETE MIXES 
The concrete mixes were designed to use locally available materials 
from a ready-mix plant and at the same time be representative of those 
mixes used for deep-ocean placement. The aggregate proportions (selected 
for pumpable concrete) were: 43% by volume of the total aggregate was 
sand, 10% by volume was 3/8-inch (9-mm) pea gravel, and 47% by volume 
was coarse aggregate of maximum l-inch (25-mm) size. Type II portland 
cement was used in conjunction with a water-reducing and retardant 
admixture (Pozzolith 300-R at a rate of 5 fl oz/100 1b of cement). 
The mix proportions and freshly mixed concrete properties for the 
low- and high-strength concretes were: 
Low-Strength Concrete 
423 1b/yd? (251 kg/m?) 
0.66 (by weight) 
3.33 (by weight) 
4.43 (by weight) 
cement content 
water/cement ratio 
sand/cement ratio 
aggregate/cement ratio 
4 in. 
3.4% (by volume) 
146.2 lb/ft? (2.37 Mg/m?) 
4 hrs 
slump 
air content 
unit weight 
setting time (Vicat) 
High-Strength Concrete 
658 lb/yd? (391 kg/m?) 
0.46 (by weight) 
2.01 (by weight) 
2.68 (by weight) 
cement content 
water/cement ratio 
sand/cement ratio 
aggregate/cement ratio 
3 in. 
2.2% (by volume) 
145.8 lb/ft? (2.34 Mg/m?) 
3 hr. 
slump 
air content 
unit weight 
setting time (Vicat) 
