Performance of rapid hardening recycled clean steel fibre materials

To minimise disruption due to repairs of concrete pavements, rapid hardening and tough materials need to be used. This paper investigates the flexural performance of rapid hardening mortar mixes made with two commercial cement types, calcium sulfo-aluminate cement and calcium aluminate cement, for thin concrete repair applications. Three-point bending tests are performed on plain and steel fibre reinforced concrete specimens containing 45 kg/m3 of recycled clean steel fibres to characterise the flexural performance of notched and unnotched prisms at different ages, ranging from one hour up to one year. The recycled fibers are shown to enhance both the flexural strength and toughness of FRC prisms, leading to hardening behaviour. Constitutive equations based on the RILEM and Model Code 2010 recommendations are found to overestimate the loading capacity of the bending tests. FE analyses using multilinear σ-ɛ tensile curves obtained by employing inverse analysis can capture better the post cracking strength and cracking pattern of the tested prisms.