Towards Development of Sustainable Ultra High Performance Fiber Reinforced Concrete (UHPFRC)

Climate change is one of the main problems that our planet faces. A challenging issue in the Civil Engineering field is to produce more sustainable materials and structures. Ultra-High Performance Fiber Reinforced Concrete (UHPFRC) is cementitious material with advantageous mechanical properties. UHPFRC can be used in a number of applications that require high-strength, ductility and durability. In the production of UHPFRC large quantities of cement, aggregates and steel fibers are required. In this investigation, Ground Granulated Blast Furnace Slag (GGBS) has been used as partial replacement of cement to produce a more sustainable UHPFRC. In addition, general purpose unprocessed recycled steel fibers have been used as an alternative to conventional new steel fibers. A comparison is made of the different types of fibers used. The results of the present study indicated that the compressive strength of HPFRC is not affected significantly for GGBS contents up to 30%. The addition of unprocessed recycled steel fibers resulted in an increase in the compressive strength of UHPFRC. In tension, the UHPFRC material presented strain softening and with an overall lower strength compared to using conventional fibers. As long fibers tend to become entangled, in the present study short recycled fibers have been used. Further study is required to investigate the use of suitably treated recycled fibers of various lengths.