Field trials with concrete incorporating biomass-fly ash. (20th October 2018) - Omran, Ahmed
Highlights: Using biomass-fly ash (BFA) in concrete reduces its landfills, concrete cost, and footprint. The use of BFA in concrete densifies concrete microstructure especially with age. BFA leads to higher mechanical strength and durability properties. A significant reduction in pore system and permeability can be observed for BFA concrete. With a given air-bubbles distribution, the BFA concrete shows excellent frost resistance. Abstract: The global cement industry contributes about 5% of carbon dioxide emission to the atmosphere, which affects greenhouse-gas emission. To address the environmental effects associated with cement manufacturing and constantly reducing natural resources, there is a necessity to develop alternative supplementary cementitious materials (ASCM) to secure sustainable concrete. Many industrial by-products such as fly ash have been employed over decades to partially substitute cement in concrete with more economic and durable concrete mixtures. Given the lack of the traditional fly ash in the near future due to the strategy of closing the coal-based electricity power plants all over the world, biomass-fly ash (a by-product of combustion of de-inking sludge, bark, and residues of woods in fluidized-bed system) can be an alternative. After successful use of biomass-fly ash as partial replacement of cement in concrete in laboratory experiments, the current research presents its long-term in-situ performance using full-scale concrete structural elements. The biomass-ash is used to replace 15%–25% of cement in normal- and fiber-reinforced concretes used for casting external and internal slabs as well as sidewalks. The results showed the possibility of using biomass-fly ash as a cement replacement with a higher mechanical strength than the reference concrete made only with Portland cement especially at an age beyond 91 days. The concrete incorporated 20% biomass-fly ash decreased the permeability, and resulted in excellent resistance to freezing-thawing and de-icing salt scaling deterioration.