A high-strength concrete resistant to elevated temperatures using steel slag aggregates

摘要

This paper investigates high-strength concrete (HSC) exposed to high temperatures using the full replacement of natural aggregates with steel slag. Polypropylene (PP) and steel fibers are used as reinforcements, and the effects of calcium aluminate cement and ordinary cement on the mechanical properties of this concrete are compared. A total of 81 cylindrical specimens of 100 × 200 mm and 81 prism specimens of 100 × 100 × 350 mm were made using different amounts of cementitious materials (cement and silica fume) of 450, 500, and 550 kg/m~3, with constant water-to-cementitious materials ratio of 0.28. The present results revealed that the HSC made with steel slag aggregates and calcium aluminate cement reinforced with steel fibers, had the greatest compressive strength of 84 and 50 MPa at temperatures of 20℃ and 800℃, respectively; and flexural strength of 7.9 and 4.5 MPa, respectively, at the same temperatures. Similar HSC specimens constructed with ordinary cement, on the other hand, performed better at 400℃. Moreover, the flexural strength of the samples placed at temperatures of 400℃ and 800℃ decreased by 28 and 48, respectively, compared to the specimens at 20℃. Compared to specimens comprised of polypropylene fibers, the fracture energy and displacement of HSC with steel slag reinforced with steel fibers subjected to high temperatures were increased by approximately 100 and 60, respectively.