Antifouling marine concrete

A method was developed for incorporating mixtures of creosote and other toxic chemicals into concrete by first impregnating a porous expanded shale aggregate with the toxic mixture. The impregnated aggregate was then mixed with portland cement and water to produce an antifouling marine concrete. Concrete panels made from aggregates impregnated with mixtures of creosote containing tributyltin oxide at levels of 100 to 250 ml per liter remained free of marine fouling for three years. The experimental antifouling concrete was not as strong as concrete made with sand and gravel, but there are well proven procedures of concrete technology that can be employed to increase its strength.