Fatigue Evaluation of Sulphate-Attacked Industrial Waste-Based Concrete Using Concrete Damaged Plasticity Model

Sulphate attack is a major cause of concrete deterioration in marine environments and its interaction with wave-induced cyclic loading exacerbates the damage. This study has evaluated strengths and fatigue performance (i.e. fatigue life, strain and residual displacement) of sulphate-attacked concrete containing silicomanganese slag, fly ash (FA) and silica fume (SF). Compressive strength, tensile strength and sulphate profile of sulphate-attacked concrete were measured experimentally. Sulphate-induced damage constitutive relations were formulated and used with concrete damaged plasticity (CDP) model to simulate fatigue loading. Experiment showed that incorporating silicomanganese slag lowered sulphate resistance by 4.8-6.6% due to increased sulphate intrusion, but synergy with FA and SF enhanced the resistance by 7.3-13.8% at 365 days. The sulphate penetration depth was 0-20 mm, and the intruded sulphate increased exponentially over time. To evaluate fatigue loading in CDP model, the non-uniform damage was determined as correlation between strength degradation and integral area of sulphate profile. Numerical results were in good agreement with experimental data from literature, with differences of 5.8-26.2% in fatigue life, 9.1-30.1% in fatigue strain and 18.1-41.9% in residual displacement. In long-term deterioration, numerical analysis found that increasing sulphate concentration significantly shortened fatigue life. Despite silicomanganese slag lowered concrete sulphate and fatigue resistance, the inclusion of FA and SF improved the durability and sustainability of concrete for potential marine applications.