Geopolymer Concrete for Sustainable Infrastructure: Functional Role of Components and Optimum Design Parameters

Geopolymer concrete (GPC) has emerged as a next-generation

sustainable construction material that can significantly reduce the

environmental impact associated with Ordinary Portland Cement (OPC).

This chapter presents a comprehensive review and design-based evaluation

of geopolymer concrete systems, highlighting the functional role of each

component and optimizing key parameters for enhanced performance.

Aluminosilicate sources (e.g., metakaolin, fly ash, volcanic tuff) react with

alkali activators such as NaOH and Na₂SiO₃ through dissolution and

polycondensation, forming N-A-S-H and C-A-S-H gels that constitute a

dense, durable binder matrix. The integration of nano-silica, graphene oxide,

and fibers (steel, basalt) further enhances microstructural compactness,

ductility, and resistance to cracking. Polycarboxylate ethers improve

workability under high alkalinity, while polyethylene glycol ensures

moisture stability during curing.

Optimal design parameters such as Si/Al (2-4), SiO₂/Na⁺ (2.0-2.5),

solid/activator (2.0-2.5), and W/B (0.3-0.35) are identified to balance

workability, polymerization efficiency, and mechanical strength. Thermal

curing at 60 ± 2 °C for 24-48 h accelerates gel transformation and yields

>90% of final strength. Experimental findings and literature data indicate

that GPC exhibits superior resistance to sulfate and acid attack, chloride ion

penetration, high temperatures (≤ 800 °C), and freeze–thaw cycles, with

minimal strength loss compared to OPC. Furthermore, boron-modified

formulations demonstrate potential as radiation and heavy metal barriers.

Although the initial material cost of GPC is higher, its lower lifetime

maintenance and replacement frequency render it economically

advantageous. Overall, multi-component geopolymer concretes represent a

technically and environmentally sustainable alternative for long-lasting

infrastructure, marine, and high-temperature applications.