Fly Ash-Based Geopolymer Composites: A Review of the Compressive Strength and Microstructure Analysis.

Area of Science:

• Materials Science
• Civil Engineering
• Environmental Science

Background:

• Geopolymer (GP) concrete offers a sustainable alternative to Portland cement (PC) concrete, reducing greenhouse gas emissions.
• Fly ash (FA), a key component in GPs, presents an opportunity for environmentally sound waste management.
• FA-GP concrete is increasingly recognized as a viable replacement for conventional concrete due to its environmental and performance benefits.

Purpose of the Study:

• To comprehensively review the clean production, mix design, compressive strength (CS), and microstructure of FA-GP concrete.
• To compile recent data and establish a comprehensive database on FA-GP concrete.
• To analyze the influence of precursor characteristics, mix design, curing, additives, and chemical activation on FA-GP concrete's CS.

Main Methods:

• Literature review of existing research on fly ash-based geopolymer concrete.
• Analysis of clean production techniques and mix design strategies.
• Compilation and critical evaluation of data on compressive strength and microstructural properties.
• Development of a database correlating precursor properties and processing parameters with CS.

Main Results:

• FA-GP concrete demonstrates mechanical and physical properties comparable or superior to PC concrete.
• Key factors influencing CS include precursor's physio-chemical properties, mix proportions, curing conditions, and activator type.
• Microstructural analysis reveals dense and homogeneous matrices in well-designed FA-GP concrete.

Conclusions:

• FA-GP concrete is a promising sustainable construction material with excellent performance characteristics.
• Understanding the interplay of various factors is crucial for optimizing FA-GP concrete production and application.
• This review provides valuable insights for researchers and practitioners seeking to utilize FA as a precursor for effective GP concrete.