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Long-Term Physical and Mechanical Properties and Microstructures of Fly-Ash-Based Geopolymer Composite Incorporating Carbide Slag
- Source :
- Materials, Volume 14, Issue 21, Materials, Vol 14, Iss 6692, p 6692 (2021)
- Publication Year :
- 2021
-
Abstract
- The long-term property development of fly ash (FA)-based geopolymer (FA–GEO) incorporating industrial solid waste carbide slag (CS) for up to 360 d is still unclear. The objective of this study was to investigate the fresh, physical, and mechanical properties and microstructures of FA–GEO composites with CS and to evaluate the effects of CS when the composites were cured for 360 d. FA–GEO composites with CS were manufactured using FA (as an aluminosilicate precursor), CS (as a calcium additive), NaOH solution (as an alkali activator), and standard sand (as a fine aggregate). The fresh property and long-term physical properties were measured, including fluidity, bulk density, porosity, and drying shrinkage. The flexural and compressive strengths at 60 d and 360 d were tested. Furthermore, the microstructures and gel products were characterized by scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS). The results show that the additional 20.0% CS reduces the fluidity and increases the conductivity of FA–GEO composites. Bulk densities were decreased, porosities were increased, and drying shrinkages were decreased as the CS content was increased from 0.0% to 20.0% at 360 d. Room temperature is a better curing condition to obtain a higher long-term mechanical strength. The addition of 20.0% CS is more beneficial to the improvement of long-term flexural strength and toughness at room temperature. The gel products in CS–FA–GEO with 20.0% CS are mainly determined as the mixtures of sodium aluminosilicate (N–A–S–H) gel and calcium silicate hydration (C–S–H) gel, besides the surficial pan-alkali. The research results provide an experimental basis for the reuse of CS in various scenarios.
- Subjects :
- Technology
Materials science
porosity
microstructure
Article
Carbide
chemistry.chemical_compound
Flexural strength
General Materials Science
Composite material
Sodium aluminosilicate
Microscopy
QC120-168.85
Aggregate (composite)
QH201-278.5
Engineering (General). Civil engineering (General)
Microstructure
fly-ash-based geopolymer
TK1-9971
Geopolymer
shrinkage
Descriptive and experimental mechanics
chemistry
Fly ash
Calcium silicate
Electrical engineering. Electronics. Nuclear engineering
TA1-2040
carbide slag
strength
Subjects
Details
- ISSN :
- 19961944
- Volume :
- 14
- Issue :
- 21
- Database :
- OpenAIRE
- Journal :
- Materials (Basel, Switzerland)
- Accession number :
- edsair.doi.dedup.....a8879c416d5985ce018b6d9351a2e180