Long-term Durability of Bitumen Modified Sulfur Polymer Concrete Under Freeze–Thaw Cycles

In this study, it is aimed to determine the durability performances of bitumen-modified sulfur polymer concrete (SPC) under the long-term freeze–thaw cycles and to examine the results in comparison with sulfur concrete (SC) and traditional Portland cement concrete (PCC). Three different bitumen ratios were selected as 2.5%, 5%, and 7.5% by weight of pure sulfur for the modification. To check whether the modification was sufficiently realized, the changes in the microstructure of the modified sulfur were examined by a polarized optical microscope, differential scanning calorimetry, and scanning electron microscope. The sulfur modification of the modified sulfur sample prepared with 2.5% bitumen addition among the selected bitumen ratios was successful. Therefore, modified sulfur prepared with this ratio was used in the preparation of SPC. SPC, SC, and PCC prepared with the similar compressive strength were subjected to 150, 300, 450, 600, and 1200 freeze–thaw cycles. After the freeze–thaw cycles, the compressive strength, ultrasonic pulse velocities, relative dynamic modulus of elasticity, and weight changes were examined. At the end of 1200 cycles, the residual compressive strength value in SC and SPC was determined 24% and 58%, while the strength test could not perform on the PCC. SPC, SC, and PCC showed a reduction in RDME 49%, 77%, and 100%, respectively. PCC could not preserve their structural integrity, while the weight loss of SPC was found to be below 1% at the end of 1200 cycles. It was determined that SPC has better durability performance under long-term freeze–thaw effects than SC and PCC.