Title: Optimization of Ultra-High-Performance Concrete Using Soft and Hard Inert Fillers (Limestone and Quartz)
Author(s): Guillermo Hernández-Carrillo, Alejandro Durán-Herrera, and Arezki Tagnit-Hamou
Publication: Materials Journal
Appears on pages(s): 275-288
Keywords: durability; filler effect; microstructure; sustainability; ultra-highperformance concrete
Ultra-high-performance concrete is a milestone of both durability and mechanical performance; nevertheless, its high consumption of clinker generates a large carbon footprint, and a large quantity of this clinker remains anhydrous due to the very low water availability in the compound. Studies of back-scattered electrons, X-ray diffraction, and quantitative energy-dispersive spectroscopy were done to propose that the cement replacement by inert fillers having a hardness between the limestone and quartz powder is possible due to a higher dissolution of both cement and silica fume that allows the formation of lower Ca/Si ratio C-S-H if enough silica
fume is present to keep porosity next to the aggregate constant. Finally, the replaced mixtures had a 37% lower carbon footprint than the reference. The results showed no difference between quartz and limestone systems—both with an adequate silica fume dosage, where able—to keep both compressive strength and bulk resistivity performance at a 37.5% cement replacement.