Abstract
This study investigates the synergistic effect of steel fibres and coarse aggregates on impact behaviour of ultra-high performance fibre reinforced concrete (UHPFRC). UHPFRC matrices with a low cement content and maximum aggregate sizes of 8 mm and 25 mm are designed by using a particle packing model. Three types of steel fibres (13 mm short straight, 30 mm medium hook-ended and 60 mm long 5D) are studied in terms of the utilization efficiencies. The results show that UHPFRC with coarser aggregates tends to have a lower cement consumption but slightly weaker mechanical strength, and the largest aggregate size is suggested to be no more than 25 mm considering the reduction on flexural toughness and impact resistance. The medium and long fibres contribute to an excellent deflection/strain hardening behaviour instead of short ones. A preferential synergistic effect on impact and flexural properties is observed between the medium fibres and the finer aggregates, while the longer fibres are more compatible to the coarser aggregates. The length of steel fibre is recommended between 2 and 5 times the maximum aggregate size. The flexural strength controls the impact resistance under low-energy impact loadings, and flexural toughness determines it under relatively high-energy (beyond energy threshold) impact loadings.
Highlights
Ultra-high performance fibre reinforced concrete (UHPFRC) pos sesses superior properties [1,2,3,4,5] due to its special mix design methods and utilized raw ingredients, usually incorporating high steel fibre content and large amount of cement [6,7,8]
This study investigates the synergistic effect of steel fibres and coarse aggregates on impact behaviour of ultrahigh performance fibre reinforced concrete (UHPFRC)
The results show that UHPFRC with coarser aggregates tends to have a lower cement consumption but slightly weaker mechanical strength, and the largest aggregate size is suggested to be no more than 25 mm considering the reduction on flexural toughness and impact resistance
Summary
Ultra-high performance fibre reinforced concrete (UHPFRC) pos sesses superior properties [1,2,3,4,5] due to its special mix design methods and utilized raw ingredients, usually incorporating high steel fibre content and large amount of cement [6,7,8]. The traditional UHPFRC consumes a large amount of cement without applying coarse aggregate to increase homogeneity and eliminate inherent weakness, such as defect of interfacial transition zone (ITZ) between matrix and coarse aggregate, stress concentration in point-topoint contact of aggregates [3,11,12] It results in a cement consump tion three times greater than normal strength concrete, causing environmental and economical burdens [13,14]. Concrete incorporating coarse aggregates can enhance volume stability [17], improve projectile impact resistance [18], achieve better workability, sometimes even a higher strength [19,20], and increase the transition point of stress-strain curves under confined conditions [21] None of these studies have systematically researched the size influence of coarse aggregates in UHPFRC systems. Coarse aggregates with the maximum size (Dmax) from 8 mm to 25 mm are utilized to investigate their influ ence on both flexural and impact properties
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
