Year: 2026
Type: article
Abstract: Sewer infrastructure worldwide is ageing beyond its designed lifespan, rendering it increasingly vulnerable to biogenic sulphuric acid corrosion, cracking, and structural collapse. Geopolymer concrete represents a promising sustainable alternative to ordinary Portland cement in such aggressive environments; however, its durability under acidic conditions remains insufficiently characterised, particularly when combined with microbial modification. This study evaluated the sulphuric acid resistance and microstructural integrity of two fly ash-based geopolymer concrete formulations—a control mixture and a Shewanella oneidensis species-enhanced bio-modified mixture (Bio)—subjected to 1% H₂SO₄ immersion at 30 °C for 10 days to simulate sewer conditions. A multi-technique analytical framework comprising mechanical testing, capillary water absorption, SEM–EDS, XRF, FTIR, and XRD was employed to elucidate degradation mechanisms and quantify the effect of bacterial modification. Bio-modified specimens exhibited a denser, more homogeneous microstructure and markedly superior acid resistance, including an 82% increase in splitting tensile strength following acid exposure, in contrast to a 13% decrease recorded in control specimens. SEM–EDS analysis confirmed reduced cracking and enhanced retention of Ca and Fe in bio-modified specimens. XRD revealed the preservation of acid-resistant crystalline phases, including quartz and andradite, in bio-modified specimens, whereas the control specimens showed greater phase decomposition and decalcification. FTIR analysis indicated greater stability of Si–O–T bonds in bio-modified specimens, consistent with reduced silicate depolymerisation. These findings confirm that Shewanella -based bio-modification significantly enhances the durability of geopolymer concrete under sulphuric acid attack, supporting its application as a resilient and sustainable material for sewer infrastructure.
Source: Materials and Structures
Institutions: Liverpool John Moores University, Universiti Malaysia Perlis
Language: English
Subfield: Environmental Engineering
Field: Environmental Science
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $3,390
Award: G6351260063
OpenAlex ID: W7204461239