The results of the tests shown above indicate that only the aquagel, 

 rotary clay and zeogel contributed materially toward making the grout 

 cohesive and resistant to erosion during the presetting period. Grout 

 with the clays added, exhibited characteristics similar to those of 

 pure clay. These properties were attributed in part to the smallness 

 of the beach sand particles because the small particles cause less 

 interruption of the micellar bonding forces of the clay. Thus, the 

 attraction between water films toughened by valence bond created a 

 grout of high plasticity. 



Materials selected . - P-95 drilling clay, said by the refiner to 

 be the micaceous fraction of illite, mined at Muroc Dry Lake, Calif., 

 was selected as the stabilizing admixture to be used in the grout because 

 it produced a harder concrete than the other clays. Hardness, more than 

 strength, was desired because the concrete barrier would be exposed to 

 sea action in places and there would be some abrasive effect upon surfaces 

 exposed to sand particles in the attacking waves. Standard test cylinders, 

 cast with materials proportioned as in test No. 8, tested l,lUO p.s.i. at 

 lU days. Mojave clay, similar to P-95 was used in the final construction. 

 Both Mojave clay and P-95 are derived from illite. The illite clays were 

 used only because of availability and suitability. Certain other clays 

 would probably be just as suitable. Clays used for the purpose should be 

 highly plastic and should homogenize readily in mixtures. 



EXPERIMENTAL CONSTRUCTION 



An experimental contract was awarded for sealing a short reach of 

 the middle jetty in December 1958. The contract provided for placement 

 of UOO cubic yards of grout in the reach of the jetty passing through the 

 surf zone. The specifications provided for the use of materials, equipment, 

 and methods as determined and ordered by the contracting officer. Contract 

 bid items were set up on the basis of operations and materials anticipated. 

 Major bid items were for (a) moving drilling equipment, (b) drilling 2-inch 

 grout holes, (c) pressure grouting, and (d) furnishing portland cement. 

 Clay and calcium chloride were Government furnished. 



The contractor moved to the job site in January 1959 with the follow- 

 ing major items of equipment. 



1 - 2-c.y. fixed drum plaster mixer. 



1 - 1-c.y. fixed drum plaster mixer. 



1 - U80-lb. wagon drill with 2-inch silicon- 

 carbide bits. 



1 - UOO c.f.m. portable air compressor. 



U - Simplex air-driven reciprocating grout pumps. 



1 - High pressure centrifugal water pump for flushing 

 sand as encountered lying on top of the jetty core. 



1 - Tank wagon to transport mixing water. 



