Durability assessment of bio-modified geopolymer concrete in simulated sewage environments

Ameri Vamkani, M, Yahya, Z, Gkantou, M ORCID: 0000-0003-2494-405X, Ferentinou, M ORCID: 0000-0001-6892-7919, Gao, Y and Bras, A (2026) Durability assessment of bio-modified geopolymer concrete in simulated sewage environments. Materials and Structures/Materiaux et Constructions, 59 (363). ISSN 1359-5997

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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.

Item Type:	Article
Uncontrolled Keywords:	Bio-modification; <italic>Shewanella</italic>-enhanced; Geopolymer concrete; Acid resistance; Sewage infrastructure; 4005 Civil Engineering; 40 Engineering; 14 Life Below Water; 12 Responsible Consumption and Production; 0905 Civil Engineering; Building & Construction; 4005 Civil engineering
Subjects:	T Technology > TA Engineering (General). Civil engineering (General) T Technology > TD Environmental technology. Sanitary engineering
Divisions:	Engineering and Built Environment
Publisher:	Springer
Date of acceptance:	24 June 2026
Date of first compliant Open Access:	24 September 2026
Date Deposited:	24 Sep 2026 13:58
Last Modified:	24 Sep 2026 13:58
DOI or ID number:	10.1617/s11527-026-03183-5
URI:	https://researchonline.ljmu.ac.uk/id/eprint/29530

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