Past Work. Lorman (Ref 4 and 5) conducted compressive strength 
tests on 3 x 6-inch (76 x 152-mm) concrete specimens that were cured in 
a simulated ocean environment of 47°F (8°C) and 600-foot (183-m) depth. 
His interest was in the strength of concrete at early ages, from 1 to 28 
days. For control tests, specimens were cured in a fog room at U9 
(23°C); others were cured in a seawater tank at 47°F (8°C) so that the 
effect of temperature could be observed. Low-slump (3.5-in., 90-mm) and 
high-slump (7-in., 180-mm) concrete mixes using five different brands of 
portland cement were investigated. 
On the average, Lorman's results showed that for low-slump concrete, 
which had a 28-day fog-cured compressive strength of 7,350 psi (50.7 
MPa), the “ocean"-cured specimens underwent a decrease in strength of 
24%, 13%, and 11% at 7, 14, and 28 days respectively, compared with 
fog-cured concrete at equal ages. For high-slump concrete, which had a 
28-day fog-cured strength of 4,950 psi (34.1 MPa), the "ocean"-cured 
specimens underwent a decrease in strength of 29%, 21%, and 18% at 7,14, 
and 28 days respectively, compared with fog-cured concrete at equal 
ages. In general, the effect of temperature caused about half of the 
decrease in compressive strength. Also, the data showed that the "ocean"- 
cured concrete developed strength more slowly than the fog-cured concrete 
and that the strengths were converging as age increased. 
Stress-Strain Behavior 
Figures 3 through 7 present the stress-strain behavior for the 
concretes, and Tables 1 and 2 show the values of Young's modulus and 
Poisson's ratio. 
The stress-strain behavior of the deep-ocean concrete appears to be 
typical of that of the fog-room and seawater-tank concretes. Values of 
Poisson's ratio for the deep-ocean concrete are lacking because of 
problems encountered in using a linear transducer to measure hoop dis- 
placement. The Young's moduli and Poisson ratios also appear to be 
typical of those of the fog-room and seawater-tank concretes. 
FINDINGS 
1. Low-strength fog-cured concrete having a uniaxial compressive strength 
of 3,300 psi (22.8 MPa) at age 28 days showed an increase in strength of 
27.9%, 27.9%, and 23.9% respectively, after 10.8 months of curing in a 
fog room, 10.2 months in a seawater tank, and 11 months in a deep-ocean 
environment at 1,830 feet (560 m). Statistically, the deep-ocean concrete 
had a strength equivalent to that of the fog-room-cured and seawater-tank- 
cured concrete. 
2. High-strength fog-cured concrete having a uniaxial compressive 
strength of 6,060 psi (41.8 MPa) at age 28 days showed an increase in 
strength of 25.7%, 14.7%, and 8.9% respectively, after 10.8 months of 
curing in a fog room, 10.2 months in a seawater tank, and 11 months in a 
deep ocean environment of 1,830 feet (560 m). The differences in strength 
were statistically significant. 
