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<p>Industrial buildings are chronically exposed to high-temperature, high-humidity, and high-concentration acidic gases (such as CO₂ and SO₂) in a coupled corrosive environment, which accelerates the neutralization of concrete, degrades its durability, and severely compromises structural safety. This study focuses on Portland cement-based materials (paste, mortar, and concrete), simulating industrial environmental conditions (50&#xa0;°C, 70% RH, 20% CO₂, and 0.9% SO₂). Through methods such as layered grinding, EDTA titration, precise carbonation measurement, XRD, thermogravimetric analysis, and microscopic morphology examination, this study systematically investigates the spatial and temporal evolution of the phase composition and content within the materials under multi-factor coupled corrosion conditions. Based on mass conservation equations for CO₂, SO₂, Ca(OH)₂, CaCO₃, and CSH, a spatiotemporal distribution model of corrosion products was established. The results indicate that carbonation dominates the initial stage of corrosion, generating CaCO₃ to fill pores. In the later stage, SO₂ decomposes carbonation products and damages the C–S–H gel, while C3A and C4AF encapsulated in the C–S–H gel dissolve into the pore solution. C4AF reacts with SO₂ to form CaSO₄, Al3⁺, and Fe3⁺. Under near-neutral pore solution conditions, Fe3⁺ precipitates as reddish-brown Fe(OH)₃. The cross-section of the corroded sample displays distinct stratified layers, including a fully sulfated zone, a partially sulfated zone, a fully carbonated zone, a partially carbonated zone, and an uncorroded zone. The numerical model accurately simulates the spatiotemporal distribution of corrosion products, providing a reliable theoretical tool and simulation foundation for the durability assessment and lifespan prediction of industrial building concrete.</p>

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Spatiotemporal evolution patterns and modeling of phase changes in cement-based materials under CO₂-SO₂ coupled corrosion

  • 期刊论文

  • 发表日期：

    2026年4月28日

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  • Zhiyuan Cao,
  • Ditao Niu,
  • Yao Lv,
  • Jie Huang

摘要

Industrial buildings are chronically exposed to high-temperature, high-humidity, and high-concentration acidic gases (such as CO₂ and SO₂) in a coupled corrosive environment, which accelerates the neutralization of concrete, degrades its durability, and severely compromises structural safety. This study focuses on Portland cement-based materials (paste, mortar, and concrete), simulating industrial environmental conditions (50 °C, 70% RH, 20% CO₂, and 0.9% SO₂). Through methods such as layered grinding, EDTA titration, precise carbonation measurement, XRD, thermogravimetric analysis, and microscopic morphology examination, this study systematically investigates the spatial and temporal evolution of the phase composition and content within the materials under multi-factor coupled corrosion conditions. Based on mass conservation equations for CO₂, SO₂, Ca(OH)₂, CaCO₃, and CSH, a spatiotemporal distribution model of corrosion products was established. The results indicate that carbonation dominates the initial stage of corrosion, generating CaCO₃ to fill pores. In the later stage, SO₂ decomposes carbonation products and damages the C–S–H gel, while C3A and C4AF encapsulated in the C–S–H gel dissolve into the pore solution. C4AF reacts with SO₂ to form CaSO₄, Al3⁺, and Fe3⁺. Under near-neutral pore solution conditions, Fe3⁺ precipitates as reddish-brown Fe(OH)₃. The cross-section of the corroded sample displays distinct stratified layers, including a fully sulfated zone, a partially sulfated zone, a fully carbonated zone, a partially carbonated zone, and an uncorroded zone. The numerical model accurately simulates the spatiotemporal distribution of corrosion products, providing a reliable theoretical tool and simulation foundation for the durability assessment and lifespan prediction of industrial building concrete.