Mapping high pH levels in hydrated calcium silicates

Engui Liu, Masoud Ghandehari, Christian Brückner, Gamal Khalil, Jill Worlinsky, Weihua Jin, Alexey Sidelev, Michael A. Hyland

Research output: Contribution to journalArticle

Abstract

Data on the variability of pH levels in cement-based materials is essential for a better understanding of the early aging of materials and the long-term performance of concrete structures. Current approaches for measuring pH levels in concrete are inadequate with respect to radiometric range and resolution and spatial granularity. We report on a methodology for mapping pH levels in concrete utilizing a halochromic porphyrin sensor molecule that allows a simple measurement of surface values of pH level using a commercial digital camera setup. As proof of concept, cement paste, mortar, and concrete samples were subject to accelerated carbonation and then evaluated for pH profiles at different ages of degradation. Comparative tests on the same specimens were also conducted using phenolphthalein as the pH indicator. Spatial distribution of pH level from pH 11.0 to 13.5 was mapped at various levels of carbonation.

Original languageEnglish (US)
Pages (from-to)232-239
Number of pages8
JournalCement and Concrete Research
Volume95
DOIs
StatePublished - May 1 2017

Keywords

  • Concrete
  • Durability
  • Pore solution
  • Reinforcement corrosion
  • pH

ASJC Scopus subject areas

  • Building and Construction
  • Materials Science(all)

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  • Cite this

    Liu, E., Ghandehari, M., Brückner, C., Khalil, G., Worlinsky, J., Jin, W., Sidelev, A., & Hyland, M. A. (2017). Mapping high pH levels in hydrated calcium silicates. Cement and Concrete Research, 95, 232-239. https://doi.org/10.1016/j.cemconres.2017.02.001