We found a match
Your institution may have access to this item. Find your institution then sign in to continue.
- Title
Strength and Microstructure of Class-C Fly Ash and GGBS Blend Geopolymer Activated in NaOH & NaOH + Na2SiO3.
- Authors
Sasui, Sasui; Kim, Gyuyong; Nam, Jeongsoo; Koyama, Tomoyuki; Chansomsak, Sant
- Abstract
In this paper, class-C fly ash (FA) and ground granulated blast-furnace slag (GGBS)-based geopolymer activated in NaOH and NaOH + Na2SiO3 was studied regarding setting time, compressive strength, porosity, microstructure, and formation of crystalline phases. When comparing the effects of alkali type on the FA and GGBS geopolymer composites, results revealed that NaOH has a lesser effect in developing strength and denser microstructure than does NaOH + Na2SiO3, since the addition of Na2SiO3 provides the silica source to develop more compact structure. Incorporation of Na2SiO3 reduced the crystallinity and the paste was more amorphous compared to NaOH activated pastes. The class-C FA and GGBS blends resulted in prolonged setting time, reduced strength, and loose matrix with the increase in fly ash content. The un-reactivity of calcium in blends was observed with increasing fly ash content, leading to strength loss. It is evident from XRD patterns that calcium in fly ash did not contribute in forming C-S-H bond, but formation of crystalline calcite was observed. Furthermore, XRD analyses revealed that the reduction in fly ash leads to the reduction in crystallinity, and SEM micrographs showed the unreactive fly ash particles, which hinder the formation of a denser matrix.
- Subjects
FLY ash; CALCIUM silicates; MICROSTRUCTURE; COMPRESSIVE strength; MIXING; POLYMER-impregnated concrete
- Publication
Materials (1996-1944), 2020, Vol 13, Issue 1, p59
- ISSN
1996-1944
- Publication type
Article
- DOI
10.3390/ma13010059