Evaluation of physical, chemical, and environmental properties of biomass bottom ash for use as a filler in bituminous mixtures

Abstract

The road construction sector is one of the most raw material-intensive sectors in existence. As a result, it has a significant impact on the environment. For this reason, there are several research projects in which industrial by-products are used as raw materials. In turn, energy production from biomass combustion is considered to be one of the most promising energy sources. However, this type of energy produces a number of wastes that need to be treated, such as biomass bottom ash. This research evaluates the properties of biomass bottom ash for use as a filler in bituminous mixtures and quantifies the environmental advantages of its use. For this purpose, the chemical composition of the ashes was analysed and their properties were physically characterised to confirm their suitability as a filler. Subsequently, the advantages of its processing compared to limestone filler, lime, or cement were calculated with SimaPro software. The results showed acceptable properties of biomass bottom ash for use as a filler, as well as a drastic reduction in the environmental impact of its processing. In short, this research presents the basis for the development of further bituminous mixtures with biomass bottom ash, reducing the extraction of raw materials and avoiding landfill disposal.