The impact of sulfate- and sulfide-bearing sand on delayed ettringite formation

Alvaro Paul, Mehdi Rashidi, Jin Yeon Kim, Laurence J. Jacobs, Kimberly E. Kurtis*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

With the increase of aggregate quarrying to meet the growing need for concrete construction comes a risk associated with new aggregate sources, which may not have uniform compositions and contain potentially harmful substances, such as sulfate and sulfide. To provide insights into the impact of sulfate- and sulfide-bearing sand on susceptibility to delayed ettringite formation (DEF), this study measures the evolution of expansion, acoustic nonlinearity (representing microscale damage), and dynamic elastic modulus of mortars prepared with varying cement compositions and exposed to an early-age high-temperature curing cycle. Samples containing sulfate- and sulfide-bearing sand show substantially higher initial levels of damage, with expansion starting at earlier ages than control samples. Damage in mortars using this sand can be attributed to accelerated decomposition of alkali-feldspar, microcracking due to relative thermal deformation between phases, early release of alkali that increases the amount of sulfate in the pore solution, and release of sulfate ions from aggregates.

Original languageEnglish
Article number104323
JournalCement and Concrete Composites
Volume125
DOIs
StatePublished - Jan 2022

Bibliographical note

Funding Information:
This material is based upon work supported by the National Science Foundation (NSF) under Grant No. CMMI-1234035 and Georgia Department of Transportation (GDOT) under Research Project No. FHWA-GA-15-1315 . Any opinions, findings, and conclusions, or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the NSF or GDOT. Authors would also like to acknowledge the assistance of Prof. Ley, from Oklahoma State University, in the μXRF-scanning elemental analysis of a mortar sample.

Funding Information:
This material is based upon work supported by the National Science Foundation (NSF) under Grant No. CMMI-1234035 and Georgia Department of Transportation (GDOT) under Research Project No. FHWA-GA-15-1315. Any opinions, findings, and conclusions, or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the NSF or GDOT. Authors would also like to acknowledge the assistance of Prof. Ley, from Oklahoma State University, in the ?XRF-scanning elemental analysis of a mortar sample.

Publisher Copyright:
© 2021 Elsevier Ltd

Keywords

  • Aggregate
  • Delayed ettringite formation (DEF)
  • Expansion
  • Microcracking
  • Sulfate

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