Concrete in sewer environments frequently experiences microbial corrosion, making an understanding of time-dependent sulfate behavior essential for durability assessments. A major challenge lies in characterizing the evolution of surface sulfate concentration on sewage pipe walls, which directly affects the erosion rate of concrete. This paper proposes an approach for monitoring and modeling the erosion rate by dividing the sulfate evolution into two phases, accumulation and stabilization, based on the surface sulfate concentration on the sewage pipe surface (SCSPS). The accumulation phase is described using a mass-balance framework incorporating biological sulfate generation, accumulation, and diffusion, while the stabilization phase is obtained by fitting experimental SCSPS data to a hydrogen sulfide (H2S) concentration model. The SCSPS model is calibrated using H2S concentration and relative humidity, and an erosion rate model is developed by integrating key parameters including H2S concentration, diffusion coefficient, and relative humidity. Model predictions effectively captured changes in sulfate concentration and erosion rate across different environmental and material conditions. Results indicate that higher H2S concentrations accelerate sulfate accumulation and concrete degradation, except at very low concentrations where SCSPS remains nearly constant. The erosion rate increases with the diffusion coefficient, with model outputs suggesting that increasing the diffusion coefficient from <InlineEquation ID="IEq1"> <EquationSource Format="MATHML"><math> <mn>5</mn> <mo>×</mo> <msup> <mn>10</mn> <mrow> <mo>−</mo> <mn>12</mn> </mrow> </msup> <msup> <mtext> m</mtext> <mn>2</mn> </msup> <mtext>/s</mtext> </math></EquationSource> <EquationSource Format="TEX">$5\times 10^{-12}\text{ m}^{2}\text{/s}$</EquationSource> </InlineEquation> to <InlineEquation ID="IEq2"> <EquationSource Format="MATHML"><math> <mn>9</mn> <mo>×</mo> <msup> <mn>10</mn> <mrow> <mo>−</mo> <mn>12</mn> </mrow> </msup> <msup> <mtext> m</mtext> <mn>2</mn> </msup> <mtext>/s</mtext> </math></EquationSource> <EquationSource Format="TEX">$9\times 10^{-12}\text{ m}^{2}\text{/s}$</EquationSource> </InlineEquation> leads to approximately a 50% increase in erosion rate during the second year. Sensitivity analysis further shows that the diffusion coefficient is the major factor governing concrete erosion under the examined conditions.

Numerical analysis of sulfate accumulation and erosion behavior of concrete in sewage pipelines

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2026年1月19日

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Libing Jin,
Linran Qiao,
Tian Wu,
Pin Zhou,
Pengfei Xue

摘要

Concrete in sewer environments frequently experiences microbial corrosion, making an understanding of time-dependent sulfate behavior essential for durability assessments. A major challenge lies in characterizing the evolution of surface sulfate concentration on sewage pipe walls, which directly affects the erosion rate of concrete. This paper proposes an approach for monitoring and modeling the erosion rate by dividing the sulfate evolution into two phases, accumulation and stabilization, based on the surface sulfate concentration on the sewage pipe surface (SCSPS). The accumulation phase is described using a mass-balance framework incorporating biological sulfate generation, accumulation, and diffusion, while the stabilization phase is obtained by fitting experimental SCSPS data to a hydrogen sulfide (H₂S) concentration model. The SCSPS model is calibrated using H₂S concentration and relative humidity, and an erosion rate model is developed by integrating key parameters including H₂S concentration, diffusion coefficient, and relative humidity. Model predictions effectively captured changes in sulfate concentration and erosion rate across different environmental and material conditions. Results indicate that higher H₂S concentrations accelerate sulfate accumulation and concrete degradation, except at very low concentrations where SCSPS remains nearly constant. The erosion rate increases with the diffusion coefficient, with model outputs suggesting that increasing the diffusion coefficient from $5 \times 10^{- 12} m^{2} /s$ $5\times 10^{-12}\text{ m}^{2}\text{/s}$ to $9 \times 10^{- 12} m^{2} /s$ $9\times 10^{-12}\text{ m}^{2}\text{/s}$ leads to approximately a 50% increase in erosion rate during the second year. Sensitivity analysis further shows that the diffusion coefficient is the major factor governing concrete erosion under the examined conditions.