Evaluation of sulfate resistance of concrete using disk specimens for a shorter testing period

Sulfate attack is one of the major durability challenges of concrete in sulfate-rich and marine environments. Conventional sulfate resistance tests are generally reliable but often require long testing periods and multiple specimen types, particularly for early-stage deterioration assessment. This study proposes the use of disk-shaped concrete specimens as an alternative testing configuration for accelerated comparative sulfate deterioration assessment. Sulfate immersion tests were conducted on disk specimens (100 mm diameter, 10 mm thickness) and conventional cylindrical specimens (100 mm diameter, 200 mm height) prepared from three different concrete mixtures and immersed in a 10% Na 2 SO 4 solution for 12 weeks. The physical and mechanical properties periodically measured for comparative evaluation included dynamic modulus of elasticity, weight change, and volumetric expansion for both specimen types, compressive strength for cylindrical specimens, and splitting tensile strength for disk-shaped specimens. The obtained experimental results were evaluated by examining the deterioration progression in disk-shaped and cylindrical specimens immersed in sulfate solution for the same 12-week period, and were further referenced against the long-term sulfate immersion results obtained from cylindrical specimens exposed to sulfate for 50 weeks. The results showed that the deterioration behaviors observed in disk specimens were generally consistent with those observed in conventional cylindrical specimens, while deterioration indicators on disk specimens appeared earlier and more clearly. Disk specimens also showed more distinct differences between concrete mixtures, whereas such differences were less clearly recognized in conventional cylindrical specimens. The proposed approach reduces testing time and simplifies specimen preparation while still maintaining the primary objective of comparative sulfate resistance evaluation for concrete.