An evaluation of bottom ash from plant biomass as a replacement for cement in building blocks

The results demonstrate that the addition of bottom ash increases the material's porosity, thereby decreasing its thermal conductivity and compressive strength. The mixture with a 1:1 Si/Ca ratio shows the best mechanical characteristics (61.11 MPa) with acceptable thermal conductivity value (0.773 W/mK) and could potentially be used in products such as building blocks, since partially replacing the cement with ash produced samples based on criteria of the EN standards. Heavy metal concentration in the leachates of the bottom ash and samples formed are far lower than those recommended in the Spanish legislation (OM AAA/661/2013) and US-EPA standard.