Shear transfer in fly ash concrete with electric arc furnace aggregates

The friction shear behaviour of concrete containing electric arc furnace (EAF) slag (hereafter called EAFC) was experimentally evaluated and compared with a reference counterpart made with only natural aggregates. Two concrete mixes were cast, both containing a cement blended with 30% fly ash to improve their sustainability. For each mix, other than analysing the main mechanical properties (compressive strength, tensile strength and elastic modulus), push-off specimens were tested to determine the shear strength, failure modes, stress–slip and stress–crack opening curves. There was a clearly enhancement in the shear strength of EAFC compared with the reference concrete, even though the relations between shear strength and tensile strength were similar for the two concretes. The results were also compared with data from the literature pertaining to ordinary concrete and recycled aggregate concrete. Existing models from both design codes and the literature were applied to the experimental results and conservative predictions were obtained in all cases. The safety margin for the EAFC was found to be higher than that for the reference concrete.