Optimization of Ultra-High-Performance Concrete Using Soft and Hard Inert Fillers (Limestone and Quartz)

• Published in: ACI materials journal Vol. 119; no. 1; p. 275
• Main Authors: Hernandez-Carrillo, Guillermo, Duran-Herrera, Alejandro, Tagnit-Hamou, Arezki
• Format: Journal Article
• Language: English
• Published: American Concrete Institute 01.01.2022
• Subjects: Building materials; Composition; High strength concrete; Limestone; Mechanical properties; Service life; Mexico
• ISSN: 0889-325X; 0889-325X; 1944-737X
• DOI: 10.14359/51734222

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 inertfillers 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. Keywords: durability; filler effect; microstructure; sustainability; ultra-high-performance concrete.