Recycled Glass and PlasticWaste in Sustainable GeopolymerSystems for Affordable Housing Solutions
Abstract
The increasing demand for sustainable construction materials has driven research into
low-carbon geopolymers that mitigate both cement-related emissions and plastic and glass
waste accumulation. This study explores the development of geopolymer concrete incorporating
fly ash (FA), slag (S), and FA + S blends, with 10% recycled crushed glass (RCG)
and recycled plastic waste (RPW) as partial coarse aggregate replacements. Compressive
strength testing revealed that FA + S-based geopolymers (25FA + S) with 100% ordinary
Portland cement (OPC) replacement achieved a 7-day strength of 24.6 MPa, representing a
98% improvement over control specimens. Slag-based geopolymers demonstrated water
absorption properties comparable to OPC, indicating enhanced durability. Microstructural
analyses using SEM, XRD, and EDS confirmed the formation of a dense aluminosilicate
matrix, with slag promoting FA reactivity and reinforcing interfacial transition zone (ITZ).
These effects contributed to superior mechanical performance and water resistance. Despite
minor shrinkage-induced cracking, full OPC replacement with S or FA + S geopolymers outperformed
control specimens, consistently exceeding the target strength of 15 MPa required
for low-impact, single-story housing applications within seven days. These findings underscore
the potential of geopolymer systems for rapid and sustainable construction, offering
an effective solution for reducing carbon footprints and repurposing industrial waste.
Keywords: recycled plastic; recycled crushed glass; green concrete; geopolymer;microstructure;
interfacial transition zone