In this work, bituminous coal, sugar cane, untreated and pretreated hazardous waste ashes are tested as supplementary cement materials, analyzing their reactivity in lime pastes prepared according to ASTM C–305, using a 0.5 water/lime ratio. The hydration process was stopped with acetone at the ages of 1, 3, 7, 14, 28, 56, 90 and 180 d. Mineral phases were determined by thermogravimetry, XRD, and SEM finding high contents of SiO2 and Al2O3 in the coal and sugarcane ashes, while in the hazardous waste ashes low contents of these oxides were found. Samples of sugarcane and untreated hazardous waste ashes seems to be attractive to be used as substitutes in the production of construction supplies. In addition to this, an E-factor analysis was carried out, which showed that carrying out fly ash replacements in any quantity contributes to the circular economy of all the economic activities involved. Reducing the amount of solid waste to be disposed of and improving the local and regional environmental quality. © 2022 The Institution of Chemical Engineers