Optimum Design for Sustainable, ‘Green’ Concrete Overlays. Part II: Shear Failure at Cracks and Inadequate Resistance to Reflection Cracking

Shear failure at cracks/joints is a major cause of degradation of concrete pave-ments. Not only it leads to serviceability problems but also introduces reflective cracks and be-comes an issue of structural integrity, durability, riding quality and safety for the users. The op-timized overlaid material, benefits from its high strength and stiffness. However, it raises some concerns regarding its shear performance due to its potential brittleness and relatively smooth fracture plane. This research makes a contribution in understanding the behaviour of a concrete pavement overlay under shear loading, and proceeds to evaluate and control reflective cracking due to shear by means of utilisation of steel fibres. The shear capacity of the mix was scrutinized experimentally employing the purposely developed single notch shear beam test. The progressive failure process was simulated using FE analysis technique. The cohesive zone model was adopted in FE simulations reflect the fibre bridging effect and aggregate interlock at crack interface. Monographs deduced from FE analysis showed the multi-cracking feature of steel fibre reinforced, polymer modified concrete overlay can provide a safe buffering zone and an effective crack control.