OPTIMAL CONTENT OF FINES AND CLAY MINERALS IN DACITE AGGREGATE, ORIGINATING FROM ''ĆERAMIDE'' QUARRY, FOR CONCRETE PRODUCTION

Eruptive rocks, as high-quality aggregates, can potentially be used for concrete production. To realise this potential, aggregates must pass, among others, specific tests concerning the quantity and quality of fine particles. The dacite aggregate was produced on a separation plant without additional washing and dusting. An increased content of fines and harmful clay minerals was found in the fine aggregate. To determine their optimal content, three concrete mixtures with different content of fines were designed in the laboratory. Concrete blocks were tested for compressive strength, flexural strength and water absorption after 7 and 28 days. The test results showed which mixture showed the best properties, and preliminary solutions were given to remove excess fine particles from the aggregate.