Dataset for article: Biomass ash as a potential material for civil engineering

The dataset was created to support the systematic characterization and comparison of fly ash and bottom ash derived from biomass combustion and co‑combustion processes in the Czech Republic. The primary objective of the data collection was to evaluate the chemical, mineralogical, and physical properties of biomass‑based ashes in relation to their potential application in civil engineering, particularly as supplementary cementitious materials. The data originate from ash samples collected from different combustion technologies, including pulverized coal combustion and fluidized bed combustion, and represent both fly ash and bottom ash fractions. The dataset includes experimentally measured chemical compositions, phase compositions, and selected physical parameters obtained using standard analytical techniques (XRF, XRD, particle size analysis). In addition, mineralogical data were evaluated to estimate the proportion of amorphous phases, which is a key indicator of potential pozzolanic activity. By providing a consolidated set of experimental results, the dataset enables comparative assessment of biomass ashes with conventional coal fly ash and with relevant requirements for construction materials. It is intended to support further research on the utilization of combustion by‑products, contribute to discussions on material variability related to fuel type and combustion technology, and facilitate data reuse in studies focusing on sustainable material development and waste valorization.