Mortars for laying and coating produced with iron ore tailings from tailing dams

•Study of mortars with iron ore tailings (IOT): physical-mechanical properties.•IOT present higher density than natural aggregates due to the iron concentration.•Mortars with IOT showed mechanical properties fitter to brick laying than regular ones.•Replacement up to 20% of lime by IOT granted satisfactory properties for coating.•IOT morphology and voids required more mixing water to obtain plasticity in mortars. Aiming to mitigate the environmental impact of the iron mining industry, this paper evaluates the technical feasibility of using iron ore tailings from tailing dams (IOT) as construction material, for mortars for laying and coating. Three mixtures were produced: conventional mortars, mortars with complete replacement of natural aggregate by IOT, and mortars replacing lime by IOT in proportions from 10% to 100%. IOT and mortars were characterised. Mortars with IOT showed increased bulk density, reduced levels of incorporated air, an increment in the amount of mixing water, and improved mechanical properties when compared with conventional ones.