Isothermal calorimetry and in-situ XRD study of the NaOH activated fly ash, metakaolin and slag

Journal Article · Mon Jan 15 04:00:00 EST 2018 · Cement and Concrete Research

DOI:https://doi.org/10.1016/J.CEMCONRES.2017.10.004· OSTI ID:22806447

Sun, Zengqing; Vollpracht, Anya ^[1]

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1. Institute of Building Materials Research (ibac), RWTH Aachen University, Schinkelstr. 3, 52062 Aachen (Germany)

Much is unknown about the reaction processes responsible for the formation and polycondensation of geopolymers and other alkali activated materials. In this work, isothermal calorimeter and in-situ XRD were adopted to study the heat and mineral evolution of NaOH activated fly ash, metakaolin and ground granulated blast furnace slag. Both activator concentration and temperature have profound influences on duration of exothermal geopolymerization peaks. NaOH activated fly ash is more temperature dependable, with much higher activation energy than metakaolin and slag. The dissolution of source precursor is rapid and the formation of new phases can be detected by the end of the initial dissolution period. The in-situ XRD measurement together with the PONKCS analysis method promotes quantitative estimation of amorphous evolution during alkali activation.

• OSTI ID: 22806447
• Journal Information: Cement and Concrete Research, Journal Name: Cement and Concrete Research Vol. 103; ISSN 0008-8846; ISSN CCNRAI
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ACTIVATION ENERGY
BLAST FURNACES
CALORIMETERS
CALORIMETRY
CONCENTRATION RATIO
DISSOLUTION
FLY ASH
HEAT
MINERALS
PRECURSOR
SLAGS
SODIUM HYDROXIDES
X-RAY DIFFRACTION