Bhushan Lal Karihaloo

The famous Wieghardt, Griffith and Irwin criteria predict the onset of fracture in linear elastic materials. They have to be supplemented by appropriate criteria for predicting the path that the...

The flexural fatigue behavior of an ultrahigh performance fiber-reinforced concrete (UHPFRC) is investigated. This UHPFRC is a self-compacting and industrially competitive version of an earlier material developed by the second author that is expensive because of the high cost of brass-coated steel fibers used in it. It is found that the distribution of fibers plays a crucial role in the fatigue resistance of this UHPFRC. Uniform distribution of fibers ensures that the material has a very high fatigue endurance limit (19 MPa)—more than 80% of its static flexural strength (24.36 MPa) at a mean stress of 44.5% (10.85 MPa)—but this decreases to approximately 64% (14 MPa) of the static strength (22.02 MPa) at a mean stress of 37% if the distribution is nonuniform with regions of few or no fibers.

The three-dimensional Lagrangian-particle-based smooth particle hydrodynamics methodology was used to simulate the flow characteristics of self-compacting concrete (SCC) mixes in an L-box test. A Bingham-type constitutive model was coupled with the Lagrangian momentum and continuity equations to simulate the flow. The simulations of SCC focused on the flow times, the free-surface profile and the distribution of large aggregates (larger than or equal to 8 mm) during the flow. The numerical simulation results were compared with actual L-box tests carried out on several SCC mixes. The comparison revealed that the methodology is very well suited to predicting the flow behaviour of SCC in terms of passing and filling abilities and the distribution of large aggregates.