In the investigation at the Civil Engineering Laboratory (CEL) , the 

 method employed to incorporate mixtures of creosote and other toxic 

 chemicals into concrete was to first impregnate a porous expanded shale 

 aggregate with the chemicals. The impregnated aggregate was then mixed 

 with Portland cement and water to produce an antifouling concrete. This 

 report describes the CEL investigation on antifouling concrete. 



MATERIALS 



Lightweight Expanded Shale Aggregate 



Expanded shale aggregates are porous and lightweight and are 

 normally used to make lightweight structural concretes which are used 

 extensively in building construction [5]. A mixture of equal weights of 

 1/4- and 3/8-inch aggregates was used to make the antifouling concrete 

 panels for the investigation described in this report. 



Portland Cement 



The American Society for Testing Materials (ASTM) , Type III, 

 Portland cement [6] was used to make the antifouling concrete panels for 

 the investigations described in this report. Type III cement (high 

 early strength cement) provides high strength in a short period (usually 

 a week or less) , and the forms can be removed in about 24 hours. 



Antifouling Chemicals 



Creosote oil conforming to Federal Specification TT-C-645A, Class 

 III [7], which is normally used for preserving marine timbers, was the 

 basic chemical impregnant for the antifouling concrete. Various toxic 

 chemicals (see Table 1) were added to the creosote oil or used separately 

 to impregnate the porous aggregate. 



METHODS 



Impregnation of Expanded Shale Aggregates 



The following procedure was employed to impregnate the dry porous 

 aggregates with the experimental antifouling chemical solutions: 



(1) A fifty-fifty mixture of 1/4- and 3/8-inch aggregates was 

 weighed. 



(2) The aggregate mixture was placed in a container and covered 

 with the experimental antifouling chemical solution. 



