Mechanical performance and post-cracking behavior of self-compacting steel-fiber reinforced eco-efficient ultra-high performance concrete

In this study the main mechanical performances of a new eco-efficient composition for ultra-high performance concrete, made with fine fly ash and low cement content, were investigated. The main tests include compressive strength, modulus of elasticity in compression, flexural strength by three and four-point bending tests and finally tensile strength through direct tensile test as well as its fresh rheology. The first-cracking strength, toughness indices and residual strength factors were evaluated by means of four-point bending test. In addition, flexural tensile strength and residual flexural tensile strength were studied through three-point bending test by quantifying energy-absorption capacity of the specimens. The results demonstrated 172 MPa and 47 GPa of compressive strength and modulus of elasticity respectively. Even with 1% vf. of micro steel fibers, noticeable post-cracking behavior including energy-absorption capacity, tensile strength and residual flexural tensile strength was observed.