Performance Evaluation of Ultra-high Performance Concrete (UHPC) and Ultra-high Performance Fibre Reinforced Concrete (UHPFRC) in Pavement Applications

UHPC and UHPFRC are distinguished materials that are utilised either partially as an overlay on an existing pavement or completely as a thin wearing slab over a base course in pavements. However, their full-scale structural applications are limited because of the significant amount of shrinkage and higher cost as compared to conventional concrete. In this article, to reduce shrinkage, UHPC and UHPFRC are developed using appreciable amount of 10 mm (nominal size) coarse aggregate by adjusting the mix of pavement quality concrete (PQC). In addition, their mechanical properties, abrasion, and shrinkage strains have been analysed. Further, extensive fatigue analysis of UHPC and UHPFRC was performed with significant number of samples. The results showed that UHPC mix exhibited a compressive strength of 100.21 MPa, a flexural strength of 11.41 MPa, and an abrasion resistance of 8.02% after 28 days of curing. Furthermore, its shrinkage strain was around 1841.51 mu mm/mm. Notably, enhancements in strength properties were observed upon introducing 2.5% steel fibers by binder volume to the UHPC designated as the UHPFRC mixture. The abrasion resistance, compressive, and flexural strength increased by 20.55%, 40.24%, and 58.52%, respectively as compared to UHPC. Furthermore, the shrinkage strain decreased significantly by 96.9% compared to the base UHPC mixture. At stress levels of 0.55-0.95, UHPC showed a 72-166% longer fatigue life than PQC, but the failure pattern is the same. After addition of fibers to UHPC, fatigue life increased by 443-146% at the same stress levels compared to UHPC without fibers.