National Academies Press: OpenBook
« Previous: BIBLIOGRAPHY
Page 49
Suggested Citation:"GLOSSARY OF TERMS." National Academies of Sciences, Engineering, and Medicine. 2012. Long-Term Performance of Polymer Concrete for Bridge Decks. Washington, DC: The National Academies Press. doi: 10.17226/14623.
×
Page 49
Page 50
Suggested Citation:"GLOSSARY OF TERMS." National Academies of Sciences, Engineering, and Medicine. 2012. Long-Term Performance of Polymer Concrete for Bridge Decks. Washington, DC: The National Academies Press. doi: 10.17226/14623.
×
Page 50

Below is the uncorrected machine-read text of this chapter, intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text of each book. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.

47 GLOSSARY OF TERMS Accelerator—See Initiator. Catalyst—See Initiator. Cross-linking agent—Bifunctional or polyfunctional monomer whose addition to a polymer system increases the rigidity, resistance to solvents, and softening point of the polymer. Curing agent—See Initiator and Hardener. Epoxy resin—A resin that contains or did contain epoxy groups principally responsible for its polymerization. Flash point—The lowest temperature at which the vapor of a combustible liquid can be made to ignite momentarily in air. Glass transition temperature (Tg)—The temperature at which an amorphous material (such as glass or a high polymer) changes from a brittle, vitreous state to a plastic state. Hardener—The chemical component added to epoxy resins that causes the resin to harden or cure. Inhibitor—Free-radical scavengers added to monomers to react with and deactivate the free radicals in growing polymer chains, and to act as antioxidants to prevent polymerization by oxidation product reaction during monomer storage. Initiator—Agent that initiates growth of polymer chains by decomposing into free radicals that actually start the chain’s growth; often incorrectly called a catalyst. Microcracks—Small, numerous, noncritical cracks that can develop in hardened concrete in the matrix and at matrix– aggregate interfaces both prior to the concrete receiving external loads or during loading. Monomer—A small molecule from which much larger poly- mer molecules can be made; usually in liquid form for concrete applications. Monomer depletion—The loss of monomer because of evaporation from the surface of hardened concrete prior to the polymerization process associated with the produc- tion of polymer-impregnated concrete. Multiple-layer overlay—Two or more layers of polymer concrete bonded to concrete; normally each layer con- sists of an application of resin with aggregate broadcast into the surface. Plasticizer—Chemical additions to monomers to improve the flexibility of inherently brittle polymers. Polymer—The product of polymerization, more commonly a rubber or resin consisting of large molecules formed by polymerization. Polymerization—The reaction in which two or more mole- cules of the same substance combine to form a compound containing the same elements, and in the same propor- tions, but of high molecular weight, from which the origi- nal substance can be regenerated, in some cases only with extreme difficulty. Polymer concrete (PC)—A composite material in which the aggregate is bound in a matrix with a polymer binder. Porosity—The ratio, usually expressed as a percentage, of the volume of voids in a material to the total volume of the material, including the voids. Premix placement—The method of initially blending a polymer binder, with fine and coarse aggregate and fill- ers, if used, and then mixing until all particles are com- pletely wetted. Once the composite has been mixed as required, it is transported and placed. Term applies to polymer concrete. Prepackaged polymer concrete—Polymer concretes whose individual components (that is, monomer or resin, fillers, and aggregates) are premeasured and packaged by the manufacturer for a prescribed sequence of introduction into the mixing process. Promoted-catalytic method—A polymerization method that uses promoters or accelerators to cause the decompo- sition of organic peroxide initiators, and subsequent release of free radicals that allow polymerization to take place at ambient temperature without the need for an external source of energy. Promoter—See Initiator. Resin—A natural or synthetic, solid, or semisolid organic material of indefinite and often high molecular weight, with a tendency to flow under stress. It usually has a softening or melting range and usually fractures conchoidally. Shelf life—Maximum interval during which a material may be stored and remain in a usable and safe condition. Silane coupling agent—Silicon compounds having the gen- eral formula (HO)3SiR were R is an organic group compat- ible with thermoplastic or thermosetting resins. They are used to enhance the chemical bond of organic polymers to inorganic materials such as sand, rock, glass, and metals. Slurry overlay—Overlay applied by placing an application of resin or monomer followed by broadcasting aggregate onto the surface.

48 Solvent—A liquid capable of dissolving another substance. Thermal-catalytic method—A polymerization method that uses chemical initiators that are dissolved in the mono- mer before introducing the mixture into the concrete. The subsequent application of external heat then causes the polymerization to occur at a rapid rate. Thermosetting—Term applied to synthetic resins that solid- ify or set on heating or curing and cannot be remelted. Thin polymer overlays (TPOs)—One or more layers of polymer concrete bonded to concrete, normally 1 in. or less in thickness. Viscosity—Friction within a liquid owing to mutual adher- ence of its particles. Low-viscosity liquid monomers flow more easily into the pores of concrete at ambient tempera- tures and pressures than do high-viscosity monomers.

Next: APPENDIX A Questionnaires »
Long-Term Performance of Polymer Concrete for Bridge Decks Get This Book
×
MyNAP members save 10% online.
Login or Register to save!
Download Free PDF

TRB’s National Cooperative Highway Research Program (NCHRP) Synthesis 423: Long-Term Performance of Polymer Concrete for Bridge Decks addresses a number of topics related to thin polymer overlays (TPOs).

Those topics include previous research, specifications, and procedures on TPOs; performance of TPOs based on field applications; the primary factors that influence TPO performance; current construction guidelines for TPOs related to surface preparation, mixing and placement, consolidation, finishing, and curing; repair procedures; factors that influence the performance of overlays, including life-cycle cost, benefits and costs, bridge deck condition, service life extension, and performance; and successes and failures of TPOs, including reasons for both.

  1. ×

    Welcome to OpenBook!

    You're looking at OpenBook, NAP.edu's online reading room since 1999. Based on feedback from you, our users, we've made some improvements that make it easier than ever to read thousands of publications on our website.

    Do you want to take a quick tour of the OpenBook's features?

    No Thanks Take a Tour »
  2. ×

    Show this book's table of contents, where you can jump to any chapter by name.

    « Back Next »
  3. ×

    ...or use these buttons to go back to the previous chapter or skip to the next one.

    « Back Next »
  4. ×

    Jump up to the previous page or down to the next one. Also, you can type in a page number and press Enter to go directly to that page in the book.

    « Back Next »
  5. ×

    To search the entire text of this book, type in your search term here and press Enter.

    « Back Next »
  6. ×

    Share a link to this book page on your preferred social network or via email.

    « Back Next »
  7. ×

    View our suggested citation for this chapter.

    « Back Next »
  8. ×

    Ready to take your reading offline? Click here to buy this book in print or download it as a free PDF, if available.

    « Back Next »
Stay Connected!