3. The low-strength deep-ocean concrete tested at pressure heads of 
1,830 feet (560 m) and 6 feet (2 m) had the same compressive strengths. 
The same was true of the high-strength deep-ocean concrete. 
4. The compressive strength of low- and high-strength deep-ocean con- 
cretes subjected to three rapid cycles of pressure to 1,830 feet (560 m) 
at a rate of 600 feet/min (3 m/s) was not affected when compared with 
that of identical specimens subjected to two cycles of pressure at a 
rate of 60 feet/min (0.3 m/s). 
5. There were no distinguishable differences in the stress-strain 
behavior of concretes cured in fog, seawater tank, or deep-ocean. 
FUTURE WORK 
The second framework containing 36 test specimens will be retrieved 
from the ocean in 1981. The specimens then will be about two years old, 
and testing similar to that reported herein will be accomplished. 
REFERENCES 
1. Civil Engineering Laboratory. Technical Note N-1544: Proposed 
method for placing freshly mixed concrete in deep ocean, by R. D. Rail 
and H. H. Haynes. Port Hueneme, Calif., Jan 1979. 
2. H. H. Haynes and R. S. Highberg. "Concrete properties at ocean 
depths," Journal of the Waterways, Harbors and Coastal Engineering 
Division, Proceedings of the American Society of Civil Engineers, vol 
102, no. WW 4, Nov 1976, pp 455-470. 
3. American Concrete Institute. Permeability of concrete to seawater, 
by H. H. Haynes. Detroit, Mich., Aug 1980, pp 21-38. 
4. Naval Civil Engineering Laboratory. Technical Report R-673: In-situ 
strength of subaqueous concrete, by W. R. Lorman. Port Hueneme, Calif., 
Apr 1970. 
Se Technical Report R-673S: Supplement to "In-situ 
strength of subaqueous concrete", by W. R. Lorman. Port Hueneme, Calif., 
Sep 1971. 
