Spray Dryer Ash from Thermoelectric Power Plants as Civil Construction Materials

Abstract

Installing flue gas desulphurization systems before particulate collectors in thermoelectric plants generates spray dryer ash (SDA), a mixture of fly ash and sulfur products. SDA carries a large environmental liability, and research to exploit this waste is still incipient. An alternative use for SDA is as raw material for civil construction. Therefore, the objective of this article is to verify the feasibility of replacing hydrated lime with SDA in rendering mortars for façades, and using SDA as a mineral addition to concrete. For this, mortar mixes with 0%, 33%, 67%, and 100% SDA replacement contents were prepared, and tests in fresh and hard states performed. For concrete, mixes with 0%, 5%, 10%, and 20% of SDA added to the cement mass were prepared, and mechanical and durability tests performed. Results show that mortar consistency tends to increase with SDA content, decreasing its workability. Mechanical and durability properties are equal to or higher than those of the reference mix, both in concrete and mortar. Also, mortar with 67% of SDA performs the best.