A comprehensive study on the effect of reinforcing methods on the flexural behaviour of Concrete-RUHTCC composite beams

Abstract

A systematic investigation on the effect of various reinforcing methods on the flexural behaviour of concrete-reinforced ultra-high toughness cementitious composites (RUHTCC) composite beams was conducted in this study, combining four-point bending tests, analytical modelling and numerical simulations. Seven specimens with steel reinforcement bars, steel wire mesh, basalt fibre fabrics, were tested, and it was found that the bending capacity of the beam increased with all these reinforcements (up to 152% comparing to that without reinforcement in this study), and various failure modes were captured including cracking in concrete and UHTCC, interfacial shear failure and interfacial peeling. An analytical model including solutions for the ultimate flexural capacity and critical strengths corresponding to interfacial shear failure and interfacial peeling was derived based on the plane-section and good material bonding assumptions. In addition, finite element models were built and used for carrying out parametric studies once they were successfully validated against experimental tests. In the end, the analytical model was further modified referring to the results of numerical parametric studies by integrating the effects of all the possible failure modes in a single expression. Thus, the proposed analytical model can be implemented and used in the design of concrete-RUHTCC composite beams.