Impact assessment of different steel fibres on mechanical, environmental and economic performance in cement mortars

The construction industry is moving towards incorporating recycled raw materials to promote sustainability, innovation and environmental responsibility. In this sense, the high economic and ecological costs derived from steel fibre production have led to the use of recycled steel fibres from end-of-life tyres as an alternative reinforcement fibre in mortars and concretes. In this research, a comparative analysis is carried out with reinforced cement mortars with three types of steel fibres: commercial, recycled with treatment and recycled without treatment. The objective is to address different solutions for the reinforcement of cement mortars from a triple perspective (functional, environmental, and economic). The laboratory results obtained for mechanical properties are analysed, followed by a discussion of their environmental performance (cradle-to-gate) and their impact on production costs. The results obtained for mortars with recycled steel fibres show that it is possible to reduce shrinkage by 19.2 %, improve flexural strength by 37.7 % and reduce CO 2 eq emissions and production costs by 23.4 % and 14.5 % respectively, compared to cement mortar reinforced with commercial steel fibres. Thus, this research provides results that support the potential application of these recycled fibres as a reinforcement material in the construction sector for a more circular and environmentally friendly industry.