Effect of age on the compressive strength of ultra-high-performance fiber-reinforced concrete

Ultra-high-performance fiber-reinforced concrete (UHPFRC) is a new type of concrete with excellent mechanical and durability characteristics. This study describes the influence of age on the compressive strength of UHPFRC. At least, 112 cubic specimens with dimensions of 100 × 100 × 100 mm were prepared. Steel fiber content, ranging from 0 to 6 percent by weight, was used as another variable in this study. Uniaxial compression tests were carried out on specimens at different ages varying from 2 to 42 days. Additionally, experimental studies were conducted on cylindrical specimens to determine the modulus of elasticity of UHPFRC specimens according to ASTM C469/C469M-14. Results showed that the increase of fiber content leads to an increase in the compressive strength of specimens. Moreover, on average, 90% of the ultimate compressive strength was achieved after only 18 days. Finally, a good correlation was demonstrated between the test data and the relevant equations proposed in literature for modulus of elasticity and compressive strength of UHPFRC.