Multivariate assessment of parameters governing sulfate attack in high-performance concrete

Particle packing methods have been increasingly adopted to produce high-performance concretes (HPCs) with reduced porosity and enhanced durability. However, the mechanisms governing external sulfate attack (ESA) in densely packed systems remain insufficiently understood, particularly regarding the relative influence of pore structure and mechanical resistance on degradation processes. The relationship between microstructural parameters and the response of particle-packed HPCs subjected to sodium sulfate exposure (10% by mass) was investigated in this study. Concretes incorporating limestone filler and silica fume, and produced with limestone or granite aggregates, were evaluated through assessments of mass variation, dimensional variation, electrical resistivity and ultrasonic pulse velocity. The experimental results were interpreted using multiple linear regression to quantify the contribution of intrinsic material parameters to ESA-induced damage. Among the investigated variables, total porosity stood out, indicating that sulfate-induced deterioration in densely packed systems is predominantly controlled by pore network characteristics. Tensile strength also showed consistent relevance, suggesting its role in counteracting internal stresses generated by expansive reaction products. In addition, the mass variation test was considered the most suitable for evaluating ESA. The findings provide a microstructure-based framework for interpreting ESA in low-porosity cementitious materials and contribute to a more fundamental understanding of durability assessment of HPCs.