Enhancing flowability and sustainability of ultra high performance concrete incorporating high replacement levels of industrial slags

• Rapid-cooling EAF oxidizing slag was applied in UHPC to substitute fine aggregates.
• Ecological benefits achieved by using less energy intensive constituents in UHPC.
• Two types of industrial slags were successfully adopted in UHPC.
• V-funnel apparatus was newly designed to evaluate filling capability of UHPC.

Ultra high performance concrete (UHPC) is an emerging construction material with its superior mechanical properties. However, UHPC requires high amount of energy intensive materials including cement, which could cause unfavorable environmental impact compared to normal concrete. Various eco-friendly UHPC mix designs are proposed by incorporating industrial slags and limestone powder in order to decrease environmental overload and enhance flowability concurrently. Particle packing analysis is carried out for mixture proportioning of the UHPC mixes using different solid constituents. Two types of industrial slags, ground granulated blast-furnace slag and rapid-cooling EAF oxidizing slag are effectively substituted cement and natural fine aggregates in UHPC, respectively. Flowability of UHPC is quantified using flow test and two V-funnel apparatus with different size. Sustainability potential of the suggested UHPC mixtures adopting various low energy intensive materials is characterized by comparing crucial environmental impact categories. Synergistic effects in flowability and ecological aspects can be achieved when two forms of industrial slags used together.