tion and polymerization characteristics, availability and cost, and the 

 properties of the resultant polymer and PIC. Liquid vinyl monomer systems 

 have generally been used. Monomers are normally supplied containing an 

 inhibitor to prevent premature polymerization of the monomer. Since 

 polymerization begins immediately on adding a promoter, its use in PIC 

 would be restricted to shallow impregnations. 



The basic method of producing polymer-impregnated concrete (PIC) 

 consists of the fabrication of precast concrete specimens, ovendrying, 

 saturation with monomer, and in-situ polymerization. 



For full impregnation, good-quality concrete having a cross section of 

 up to 305 millimeters (12 inches) will require soaking in monomer for about 

 60 minutes under a pressure of 69 kilopascals (10 pounds per square inch). 

 Concrete may be only partially impregnated when improved strength is not 

 needed but greater durability is desired. 



(3) Polymer-Portland Cement-Concrete . Polymer-Portland cement- 

 concrete (PPCC) has been prepared with both premixed and postmixed poly- 

 merized materials. The premixed polymerized materials include latexes and 

 polymer solutions or dispersions. The postmix polymerized PPCC has been 

 made with a number of resins and monomers. 



(a) Polymer Latexes . At present, latex-modified concretes 

 represent the large majority of commerical applications of polymer-modified 

 concretes in the United States. Suitable latex formulations greatly 

 improve the shear bond, tensile, and flexural strength of cements and 

 mortars. 



(b) Polymer Solutions . Thermosetting water-soluble polymers 

 which have been added to fresh concrete include epoxies, amino-resins, 

 polyesters, and formaldehyde derivatives. Thermoplastic materials include 

 polyvinyl alcohol and polyacrylamides. 



PPCC process technology is based upon overcoming the incompatibilities 

 of most organic polymers and their monomers with mixtures of Portland 

 cement, water, and aggregate. The mix proportioning of latex PPCC will 

 vary in much the same way as do normal concretes and mortars. 



(4) Polymer Concrete. Most of the work on polymer concrete (PC) 

 has been with polyester styrene resin systems, and to a lesser extent with 

 furan, epoxy, and vinylester resins systems. The polyester resins are 

 attractive because of moderate cost, availability of a great variety of 

 formulations, and moderately good PC properties. 



Most of the monomer and resin systems for PC are polymerized at 

 ambient temperatures. Vinyl monomer systems can be polymerized with 

 catalysts such as benzoyl peroxide with an amine promoter. The polyester- 

 styrene systems are polymerized with promoter-catalyst systems such as 

 methylethyl ketone peroxide with cobalt napthanate promoter. Other 

 systems include amine curing agents for epoxy resins. 



Mixing and placing techniques for PC are based on adaptation of existing 

 equipment and methods for producing Portland cement concrete. A knowledge 



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