Reutilisation of hazardous spent fluorescent lamps glass waste as supplementary cementitious material

[Display omitted] •Spent fluorescent lamps glass (SFLG) waste successfully used to replace PC.•No prior treatment required to reduce the mercury content of SFLG.•Similar pozzolanic activity observed with manual and mechanically treated SFLG.•Strength results came close to 100% PC, with up to 35% SFLG after 90 curing days.•SFLG waste generally prolonged the setting time of the blended pastes. Spent fluorescent lamps glass (SFLG) waste, manually and mechanically processed in a lamps waste treatment plant, was used to partially replace up to 50 wt% Portland cement (PC). Both waste types exhibited similar pozzolanic activity. The mortars containing up to 35 wt% SFLG met the specifications for other pozzolanic materials (e.g. fly ash) and, after 90 curing days, their compressive strength values were similar to or higher than those of the 100% PC sample (58.8 MPa). Our results provide an alternative reutilization process for this hazardous waste to reuse SFLG as-received (no washing to reduce mercury) and contributes to less PC use.