The study was based on the replacement of Portland cement with different proportions of biomass ash (from 10% to 90%).
Scientists have used the ashes derived from the combustion of a biomass mix, i.e. a mixture of pomace and agricultural waste (pruning of olive groves, vines and fruit trees) and energy crops (poplar).
Biomass generates two types of ash, one that is deposited in the boilers and is called bottom ash, and a second one that is formed by the particles that are dragged by the combustion gases and deposited in the filters, called fly ash.
In initial studies, better results were obtained with bottom ash, which is nowadays removed and ends up in the landfill. Fly ash, on the other hand, caused problems of durability and expansivity, and is already useful as a fertiliser for crops.
According to a study by the Escuela Politécnica Superior de Linares of the University of Jaén .
"We have tested all the proportions of components and the ones with the best properties are those mixtures that include half Portland cement and half ash. The rest, above the 50% ash addition, crack and spall on freezing and thawing," explains Bartolomé Carrasco Hurtado, one of the researchers responsible for the study.
