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Internal Curing Using Superabsorbent Polymers for Alkali Activated Slag-Fly Ash Mixtures

  • Ying WangEmail author
  • Luca Montanari
  • W. Jason Weiss
  • Prannoy Suraneni
Conference paper
Part of the RILEM Bookseries book series (RILEM, volume 24)

Abstract

Increased shrinkage is often noted as a concern for alkali activated materials. In this study, two slag-fly ash paste and mortar mixtures with slag:fly ash ratios of 30:70 and 50:50 activated using 4M sodium hydroxide are formulated. The effects of two dosages of a commercial superabsorbent polymer (SAP) on the reaction heat, strength gain, autogenous shrinkage, drying shrinkage, and mass loss behavior are presented here. The SAP increases the heat of reaction of the alkali activated pastes, however, this increase is less than 5% at 7 days. The SAP slightly decreases the compressive strength of the alkali activated mortars, and this decrease is generally less than 10% at 1, 7, and 28 days. The SAP significantly reduces the ultimate autogenous shrinkage (by more than 50%) and reduces the drying shrinkage (by 15–30%) of the mortars. Mixtures with SAP have autogenous shrinkage between 50–300 με and drying shrinkage between 600–700 με. When SAP is used, the mass loss in the mortars increases, however, the slope of the mass loss-drying shrinkage curve decreases. Shrinkage mitigation in the studied mixtures increases as the SAP dosage increases. Further studies on this system, and on other binders, activator combinations, and SAP types are currently ongoing.

Keywords

Superabsorbent polymers Alkali activated materials Fly ash Slag 

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Copyright information

© RILEM 2020

Authors and Affiliations

  • Ying Wang
    • 1
    Email author
  • Luca Montanari
    • 2
  • W. Jason Weiss
    • 3
  • Prannoy Suraneni
    • 1
  1. 1.Department of Civil, Architectural, and Environmental EngineeringUniversity of MiamiCoral GablesUSA
  2. 2.SES Group and Associates LLCTurner-Fairbank Highway Research CenterMcLeanUSA
  3. 3.School of Civil and Construction EngineeringOregon State UniversityCorvallisUSA

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