TABLE 13 - COST COMPARISON BETWEEN STANDARD CONCRETE AND 



IMPREGNATED POROUS SHALE ANTIFOULING CONCRETE 



FOR A 3-IN. -THICK COVERING ($/Ft2) 



Location 



Standard Concrete 



Antifouling Concrete | 



Regular 



Lightweight 



Regular 



Lightweight 



Florida 

 Hawaii 



0.19 

 0.37 



0.31 

 0.42 



5.08 

 5.26 



5.20 

 5.31 



In a third method, a polymer impregnation of cured structural concrete 

 surfaces results in a layer of poljnner which penetrates to 1 in. below the 

 surface of the concrete. In this case the concrete is expected to absorb 

 5 percent of the weight of the monomer or polymer solution after solvent 

 evaporation. This produces a flat material cost of approximately $3.13/ 

 ft for the antifouling organometallic monomer solution. These methods 

 appear to be much cheaper than the impregnated-shale method previously men- 

 tioned, but many inherent hidden costs are present in these systems. Even 



12 

 though these materials have exhibited good antifouling performance, they 



have never been used in this manner, and suitable means of achieving good 

 concrete surface layer penetration must be developed. In addition, with 

 the monomer, free radical polymerization of the antifouling monomer must 

 take place uniformly in the concrete. This has been done in the past by hot 

 water immersion or gamma ray irradiation. A large-scale technique to accom- 

 plish this polymerization would have to be developed. These considerations 

 may raise the final cost of these systems to prohibitive levels, but the 

 initial low material costs may merit further investigation in the areas of 

 application and in-situ poljmierization. 



Finally, in the cost of polymer concrete, it is assumed that this 

 material is applied in a 3-in. surface shell over the structural concrete 



with monomer comprising 8 percent of the weight of the wet mixture. This 



2 2 



produces a cost of approximately $4.67/ft in Florida and $4.73/ft in 



Hawaii for polymer concrete, with the antifouling monomer component being 



the determining cost factor. 



51 



