Unclassified 
SECURITY CLASSIFICATION OF THIS PAGE(When Data Entered) 
20. Continued 
coatings on untreated concrete. Test specimens were exposed at Port Hueneme, Calif., and 
Key Biscayne, Fla. Efficacy of toxicants was determined by periodically weighing the speci- 
mens and the fouling organisms that became attached. Concrete prepared with an aggregate 
impregnated with a TBTO/creosote mixture demonstrated the best antifouling performance 
of those specimens exposed for more than 1 year. The two proprietary coatings and the 
concrete containing methoxychlor, TPTH, and cuprous oxide as dry additives have ex- 
hibited good antifouling properties but have been exposed for a shorter time. Also, the 
strength of concrete prepared using the toxicants was acceptable, and the corrosion rate of 
reinforcing rods did not increase. The concentration of organotin compounds was essentially 
unchanged in a concrete specimen exposed 6-1/2 years in seawater. 
Library Card 
CIVIL ENGINEERING LABORATORY 
ANTIFOULING MARINE CONCRETE (Final), by C. W. Mathews 
TN-1573 March 1980 37 pp illus Unclassified 
1. Antifouling concrete 2. OTEC I. EG-77-A-29-1104 
Various toxic agents were investigated for their ability to prevent the attachment and 
growth of marine fouling organisms on concrete. Three methods of incorporating antifoulants 
into concrete were also studied. Porous aggregate was impregnated with creosote and 
bis-(tri-n-butyltin) oxide (TBTO) and then used in making the concrete. Cuprous oxide, tri- 
phenyltin hydroxide (TPTH), and 2-2-bis-(p-methoxyphenyl)-1, 1, 1-trichloroethane (methoxychlor) 
were used as dry additives. Two proprietary formulations were applied as coatings on untreated 
concrete. Test specimens were exposed at Port Hueneme, Calif., and Key Biscayne, Fla. Efficacy 
of toxicants was determined by periodically weighing the specimens and the fouling organisms 
that became attached. Concrete prepared with an aggregate impregnated with a TBTO/creosote 
mixture demonstrated the best antifouling performance of those specimens exposed for more than 
1 year. The two proprietary coatings and the concrete containing methoxychlor, TPTH, and 
cuprous oxide as dry additives have exhibited good antifouling properties but have been exposed 
for a shorter time. Also, the strength of concrete prepared using the toxicants was acceptable, and 
the corrosion rate of reinforcing rods did not increase. The concentration of organotin compounds 
was essentially unchanged in a concrete specimen exposed 6-1/2 years in seawater. 
Unclassified 
SECURITY CLASSIFICATION OF THIS PAGE(When Data Entered) 
