a 4.0 



1 I 



Spheres of 66-in.-OD by 4.12-in. wall 



O Coated exterior 

 /\ Uncoated exterior 



Accuracy of each datum point 

 is ±0.24 ft^ (7 liters). 



Depth (ft) 

 A 4,185 



Time in Ocean (yr) 

 Figure 24. Total water intake for spheres in the ocean for long time periods. 



that extrapolations of the pressure vessel 

 test results yield results close to the 

 actual values obtained from the spheres 

 in the ocean. 



The data from the spheres compared 

 moderately well vi'ith results from 

 Powers et al. vRef 10) who studied 

 cement pastes. The water-to-cement 

 ratio for the pastes varied from 0.3 to 

 0.7, and the measured K^- values (initial 

 tangent Kc ) ranged from 0.3 x IQ-^'^to 

 WO X 10-1^ ft/sec (0.1 X lO-^'^ to 120 x 

 lO^^^m/sec), respectively. 



For a water-to-cement ratio of OA, 

 which was equivalent to that for the 

 concrete in the spheres, Power's results 

 showed a Kc of about 3.3 x 10'^^ tt/sec 



(1.0 X 10-^^m/sec). This was an order of 

 magnitude lower than that for the con- 

 crete in the spheres tested in the pres- 

 sure vessels. Powers did not discuss any 

 indication of permeability results 

 decreasing with time, as was found in 

 this study. 



Durability 



Samples of 5.6-year-old concrete 

 from the ocean spheres, both coated and 

 uncoated, and from the on-land and 

 continuously fog-cured cylinders were 

 analyzed by x-ray diffraction techniques 

 by Prof. Mehta at the University of 

 California at Berkeley. He determined 



32 



