Mechanical performance of full-scale precast steel fibre-reinforced concrete pipes

This paper reports the findings of a laboratory-testing program performed on full-scale precast concrete pipes reinforced with dispersed steel fibres. Steel fibre reinforced concrete (SFRC) pipes had diameters of 450 and 600 mm. Two types of steel fibres having round cross-sections and hooked ends were used. Steel fibres had lengths and aspect ratios of 35 and 60 mm, and 65 and 80, respectively. The steel fibres content ranged from 0 to 40 kg/m3. Plain (PC) and conventionally reinforced (RC) precast concrete pipes were also tested for comparison. Tested specimens were instrumented with strain gauges mounted on critical sections of each pipe. In addition, vertical and horizontal deformations of the pipe's cross-section were monitored using LVDTs. Precast pipes were tested using both the continuous and cyclic loading procedures as per the ASTM C497 and EN 1916 guidelines, respectively. Results showed that a fibre dosage of 30 kg/m3 satisfied the strength requirements of ASTM C76 Class V pipe for 450 and 600 mm diameter pipes. In addition, the post-peak behaviour of SFRC pipes was comparable or superior to that of conventional RC pipes at small deformations. It was also found that the behaviour of SFRC pipes could be fully explored using the continuous three-edge-bearing test without need of an extra loading cycle as specified in the EN 1916 standard.