Interlaboratory evaluation of Tg of ambient-cured epoxies used in civil infrastructure

Charles E. Bakis, Luke A. Bisby, Maria M. Lopez, Sarah E. Witt, Tarek Alkhrdaji

Research output: Chapter in Book/Report/Conference proceedingConference contribution

4 Citations (Scopus)

Abstract

Ambient-cured epoxies used to bond high strength continuous fibers to concrete for strengthening purposes can have glass transition temperatures (Tg) that are not only close to the service temperature but can also change over time as a function of environmental conditions. While the design ramifications of using such an epoxy resin with an evolving Tg close to the service temperature are unclear and difficult to predict, recommended methods for assigning a Tg for such resins are nonetheless needed. In the present investigation, an interlaboratory evaluation of Tg characteristics of several ambient-cured epoxy resins using dynamic mechanical analysis (DMA) and differential scanning calorimetry (DSC) was carried out. The need for standardized specimen conditioning prior to Tg measurement is demonstrated. Of the three DMA Tg methods employed, the tan δ method provided the lowest standard deviation. Because of its reliability and its roots in mechanical testing, the DMA tan δ method applied during a single temperature up-ramp is recommended for assigning Tg.

Original languageEnglish (US)
Title of host publicationProceedings of the 7th International Conference on FRP Composites in Civil Engineering, CICE 2014
EditorsRaafat El-Hacha
PublisherInternational Institute for FRP in Construction (IIFC)
ISBN (Electronic)9781771363082
StatePublished - Jan 1 2014
Event7th International Conference on FRP Composites in Civil Engineering, CICE 2014 - Vancouver, Canada
Duration: Aug 20 2014Aug 22 2014

Publication series

NameProceedings of the 7th International Conference on FRP Composites in Civil Engineering, CICE 2014

Other

Other7th International Conference on FRP Composites in Civil Engineering, CICE 2014
CountryCanada
CityVancouver
Period8/20/148/22/14

Fingerprint

Dynamic mechanical analysis
Epoxy Resins
Epoxy resins
Mechanical testing
Strengthening (metal)
Temperature
Differential scanning calorimetry
Resins
Concretes
Fibers

All Science Journal Classification (ASJC) codes

  • Polymers and Plastics
  • Civil and Structural Engineering

Cite this

Bakis, C. E., Bisby, L. A., Lopez, M. M., Witt, S. E., & Alkhrdaji, T. (2014). Interlaboratory evaluation of Tg of ambient-cured epoxies used in civil infrastructure. In R. El-Hacha (Ed.), Proceedings of the 7th International Conference on FRP Composites in Civil Engineering, CICE 2014 (Proceedings of the 7th International Conference on FRP Composites in Civil Engineering, CICE 2014). International Institute for FRP in Construction (IIFC).
Bakis, Charles E. ; Bisby, Luke A. ; Lopez, Maria M. ; Witt, Sarah E. ; Alkhrdaji, Tarek. / Interlaboratory evaluation of Tg of ambient-cured epoxies used in civil infrastructure. Proceedings of the 7th International Conference on FRP Composites in Civil Engineering, CICE 2014. editor / Raafat El-Hacha. International Institute for FRP in Construction (IIFC), 2014. (Proceedings of the 7th International Conference on FRP Composites in Civil Engineering, CICE 2014).
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Bakis, CE, Bisby, LA, Lopez, MM, Witt, SE & Alkhrdaji, T 2014, Interlaboratory evaluation of Tg of ambient-cured epoxies used in civil infrastructure. in R El-Hacha (ed.), Proceedings of the 7th International Conference on FRP Composites in Civil Engineering, CICE 2014. Proceedings of the 7th International Conference on FRP Composites in Civil Engineering, CICE 2014, International Institute for FRP in Construction (IIFC), 7th International Conference on FRP Composites in Civil Engineering, CICE 2014, Vancouver, Canada, 8/20/14.

Interlaboratory evaluation of Tg of ambient-cured epoxies used in civil infrastructure. / Bakis, Charles E.; Bisby, Luke A.; Lopez, Maria M.; Witt, Sarah E.; Alkhrdaji, Tarek.

Proceedings of the 7th International Conference on FRP Composites in Civil Engineering, CICE 2014. ed. / Raafat El-Hacha. International Institute for FRP in Construction (IIFC), 2014. (Proceedings of the 7th International Conference on FRP Composites in Civil Engineering, CICE 2014).

Research output: Chapter in Book/Report/Conference proceedingConference contribution

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N2 - Ambient-cured epoxies used to bond high strength continuous fibers to concrete for strengthening purposes can have glass transition temperatures (Tg) that are not only close to the service temperature but can also change over time as a function of environmental conditions. While the design ramifications of using such an epoxy resin with an evolving Tg close to the service temperature are unclear and difficult to predict, recommended methods for assigning a Tg for such resins are nonetheless needed. In the present investigation, an interlaboratory evaluation of Tg characteristics of several ambient-cured epoxy resins using dynamic mechanical analysis (DMA) and differential scanning calorimetry (DSC) was carried out. The need for standardized specimen conditioning prior to Tg measurement is demonstrated. Of the three DMA Tg methods employed, the tan δ method provided the lowest standard deviation. Because of its reliability and its roots in mechanical testing, the DMA tan δ method applied during a single temperature up-ramp is recommended for assigning Tg.

AB - Ambient-cured epoxies used to bond high strength continuous fibers to concrete for strengthening purposes can have glass transition temperatures (Tg) that are not only close to the service temperature but can also change over time as a function of environmental conditions. While the design ramifications of using such an epoxy resin with an evolving Tg close to the service temperature are unclear and difficult to predict, recommended methods for assigning a Tg for such resins are nonetheless needed. In the present investigation, an interlaboratory evaluation of Tg characteristics of several ambient-cured epoxy resins using dynamic mechanical analysis (DMA) and differential scanning calorimetry (DSC) was carried out. The need for standardized specimen conditioning prior to Tg measurement is demonstrated. Of the three DMA Tg methods employed, the tan δ method provided the lowest standard deviation. Because of its reliability and its roots in mechanical testing, the DMA tan δ method applied during a single temperature up-ramp is recommended for assigning Tg.

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Bakis CE, Bisby LA, Lopez MM, Witt SE, Alkhrdaji T. Interlaboratory evaluation of Tg of ambient-cured epoxies used in civil infrastructure. In El-Hacha R, editor, Proceedings of the 7th International Conference on FRP Composites in Civil Engineering, CICE 2014. International Institute for FRP in Construction (IIFC). 2014. (Proceedings of the 7th International Conference on FRP Composites in Civil Engineering, CICE 2014).