Materials, Methods & Technologies, Volume 15, 2021

Rezumat: Fly ash, ground granulated blast furnace slag and silica fume are often used cementitious materials for concrete production in Germany. Caused by environmental issues and the withdrawal from coalbased energy production, it is expected that fly ash will be widely replaced by other suitable materials when producing concrete in future. In this context, the interest in so far minor applied cementitious materials like metakaolin and rice husk ash is increasing, presently. The paper reports an experimental investigation where different amounts of fly ash, blast furnace slag, silica fume, metakaolin, and rice husk ash were applied in concrete mixes. The research was focused on the influence of the various cementitious materials on the time–dependent concrete compressive strength development. For this, cube compressive strength was measured in concrete age of 1, 3, 7 and 28 days. As a main result it can be stated that silica fume and rice husk ash have comparable influence on the concrete strength. Metakaolin also contributes to the concrete strength development, but the experiments highlighted that it is reducuing the workability of fresh concrete, too.