Appendix D 

 CEMENT PASTE SAMPLES PLACED IN THE OCEAN 



To study the phenomenon of magne- 

 sium ions replacing calcium ions in 

 tobormorite gel, small neat cement paste 

 samples were mounted on the chain of 

 Spheres no. 15 and 16 on 7 Mar 1978. Ten 

 samples were placed, five at each 

 sphere. The samples were 1 inch in 

 diameter by 2 inches long (25 x 51 mm). 

 They were suspended from a steel bar 

 that was hooked onto the sphere chain. 

 The samples were hung from insulated 

 electrical cables about 1.5 feet {0.5 m) 

 below the bar. Each cable contained a 

 plug-in type connector (Figure D-1). In 

 the future to retrieve a sample, a 

 submersible can use its manipulators to 

 disconnect the plug. 



The cement paste samples were pre- 

 pared on 1 3an 1978 by Professor P. K. 

 Mehta of the University of California at 

 Berkeley. The paste was made of Type 11 

 Portland cement having a water-to- 

 cement ratio of 0.60. The relatively high 

 water-to-cement ratio was used to 

 create a higher-than-normal porosity. 

 The samples were made using a 

 technique that prevented bleeding. 



The chemical composition for the 

 cement is given in Table D-1. 

 Comparison samples to those in the 

 ocean were placed in a fog room 

 environment at CEL and the University 

 of California at Berkeley. 



Table D-1. Chemical Composition of 

 Portland Cement 



Chemical 



Percent 



Si02 



AI2O3 



Fe203 



CaO 



MgO 



SO3 



22.36 

 3.75 

 2.10 



65.89 

 1.77 

 2.29 



C3S 



C2S 

 C3A 

 C4AF 



63.5 



16.3 



6.4 



6.4 



Blaine, cm^/g 4,800 



f5 



