Development of Geopolymers Based on Fly Ashes from Different Combustion Processes.

Area of Science:

• Materials Science
• Chemical Engineering
• Civil Engineering

Background:

• Fly ash utilization in geopolymer production offers a sustainable alternative to traditional cement.
• Geopolymer properties are highly dependent on the characteristics of the precursor fly ash.
• Understanding the influence of different fly ash sources is crucial for optimizing geopolymer performance.

Purpose of the Study:

• To assess the suitability of three distinct fly ashes as raw materials for geopolymer manufacturing.
• To investigate the impact of fly ash origin and processing temperature on geopolymer properties.
• To evaluate the mechanical performance of geopolymers derived from conventional, ultra-fine, and waste incineration fly ashes.

Main Methods:

• Characterization of fly ashes using X-ray fluorescence (XRF) and X-ray diffraction analysis (XRD).
• Microstructural analysis using Scanning Electron Microscopy (SEM).
• Evaluation of geopolymer mechanical properties, including density, compressive strength, and flexural strength.

Main Results:

• Geopolymer materials exhibited comparable compressive strengths (around 60 MPa) across all tested fly ashes.
• Significant variations in flexural strength were observed, ranging from 0.1 MPa to 5.3 MPa.
• Ultra-fine fly ash resulted in lower flexural strength compared to conventional fly ash.

Conclusions:

• Fly ash type significantly influences the flexural strength of resulting geopolymers.
• Precursor characterization is essential for predicting geopolymer performance.
• Further process optimization is required for geopolymers utilizing waste incineration plant fly ash to achieve desired mechanical properties.