Strain-hardening cementitious composite from supersulfated ladle slag cement with polypropylene fibers

This investigation focuses on the recycling of ladle slag from steel making industry. The supersulfated ladle slag cement (SLC) was produced by the hydration between ladle slag and gypsum. The main reaction product is ettringite. Additionally, due to the brittleness of matrix, polypropylene (PP) fiber was employed as reinforcement with a content of 2% by volume. The mechanical performance of cementitious composite was assessed considering flexural, compressive, uniaxial tensile loading and the fracture toughness. The experimental results reveal that the PP fibrous reinforcement offered important improvements in the mechanical performance of SLC compared to the unreinforced counterpart. Fracture energy and fracture toughness of the reinforced SLC were roughly 125 and 5 times higher than that of the plain material. Moreover, the flexural strength increased by 130% with the use of PP fiber; the compressive strength reached 45.5 MPa after 28 days of curing in water. Under uniaxial tensile load, the composite developed multiple fine cracks with strain hardening behavior observed by Digital Image Correlation (DIC) technique while the unreinforced material exhibited a typical brittle failure. The composite offers a waste-based solution to be used in high-value applications with relatively low volume such as rapid repair materials.