made with the right materials and mix proportions, and placed correctly 

 with adequate and well compacted cover, was a durable, long-lasting mate-' 

 rial requiring little maintenance. 



Recent Developments in Concrete Technology 



Polymer concrete and polymer-impregnated concrete are recent develop- 

 ments in concrete technology that may have application to OTEC power plant 

 structures and components. Polymer concrete (PC) consists of cement and 

 an aggregate mixed with a monomer resin which is subsequently polymerized 

 in place.-'--' Manson-*-" defines poljmier concrete as a composite in which a 

 thermoplastic or cross-linked polymer is used to replace all or part of 

 the Portland cement as the binder in a concrete mix. Techniques for mixing 

 and placement are similar to those used for Portland cement. After curing, 

 a high-strength, durable material results. Kukacka and Steinberg reported 

 several important properties of PC measured on specimens containing oven- 

 dried aggregate and containing 7- to 8-percent monomer by total weight of 

 wet mix. The enhanced durability properties are significant; for example, 

 water absorptions of 1 percent are normally obtained. 



Keeton and Alumbaugh-'-^ investigated the strength and strength-ratio 

 properties of polymer-cement mortar and polymer-cement-concrete composites 

 formulated with (1) epoxy, polyester, and epoxy-acrylate resins; (2) acrylic, 

 vinyl acetate, styrene-butadiene, and polyvinylidene chloride latices in 

 varying proportions in relation to the weight of the cement. ASTM Type III 

 Portland cement and regulated set cements were used. Compressive strength 

 values are summarized in Table 1. 



Polymer-impregnated-concrete (PIC)-'-^ is the most highly developed of 

 the concrete-polymer composites and provides the greatest improvements in 

 structural and durability properties. For a straight concrete mix which 

 produces specimens with compressive strengths of 35 MPa (5000 psi) , com- 

 pressive strengths of 140 MPa (20,000 psi) are generally obtained after 

 impregnation with monomer and subsequent curing. Design values for PIC 

 that cover the range of monomer systems used and other types of concrete 

 have been published. 1^ These values are summarized in Table 1. 



