Microstructural and Mineralogical Analysis of Alkali Activated Fly Ash-Slag Pastes

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Abstract

The performances of alkali activated materials (AAM) are strongly related to their microstructures. The microstructure development is mainly affected by chemistry of the primary raw materials. In the present study the influence of different proportions of fly ash and slag (100:0, 70:30, 50:50, 30:70, 0:100 wt.%, named S0, S30, S50, S70, S100, respectively) on the microstructure and mineralogy of the alkali activated fly ash and slag based pastes has been investigated through XRD, TGA/DTGA, ESEM/EDX techniques. XRD has been used for the qualitative and quantitative analysis of different reaction products.
The Rietveld refinement method and TGA/DTGA analysis have demonstrated that the increase of slag content increased the amount of amorphous phase associated with gel formation. From ESEM results, a more refined and denser matrix has been deduced in slag rich mixtures. These results are in agreement with higher strength values observed for S70 and S100 mixtures (~100 MPa at 28d and ~120 MPa after 90d curing). Depending on the fly ash to slag ratio, two types of gel have been distinguished by EDX analysis, a N-A-S-H gel in the fly ash rich mixtures and a C-A-S-H gel in the slag rich pastes.
Original languageEnglish
Title of host publication3rd International RILEM Conference on Microstructure Related Durability of Cementitious Composites
Subtitle of host publicationNanjing, China
EditorsChangwen Miao, Wei Sun, Jiaping Liu, Huisu Chen, Guang Ye, Klaas van Breugel
PublisherRILEM publications S.A.R.L
Pages1-10
Number of pages10
Volume117
ISBN (Electronic)978-2-35158-189-6
ISBN (Print)978-2-35158-188-9
Publication statusPublished - 2016
Event3rd International Conferences on Microstructure Related Durability of Cementitious Composites - Nanjing, China
Duration: 24 Oct 201626 Oct 2016
Conference number: 3
http://www.microdurability2016.com/

Conference

Conference3rd International Conferences on Microstructure Related Durability of Cementitious Composites
Abbreviated titleMicrodurability 2016
CountryChina
CityNanjing
Period24/10/1626/10/16
Internet address

Keywords

  • Alkaline activation
  • Fly ash
  • Slag
  • Gel composition
  • Mineralogy

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  • Cite this

    Nedeljkovic, M., Arbi Ghanmi, K., Zuo, Y., & Ye, G. (2016). Microstructural and Mineralogical Analysis of Alkali Activated Fly Ash-Slag Pastes. In C. Miao, W. Sun, J. Liu, H. Chen, G. Ye, & K. van Breugel (Eds.), 3rd International RILEM Conference on Microstructure Related Durability of Cementitious Composites: Nanjing, China (Vol. 117, pp. 1-10). RILEM publications S.A.R.L.