Heated stone powder substitute for metakaolin-based geopolymer

Abstract

This study aims to provide a new substitute material for metakaolin (MK), which is the primary binder material of geopolymer composites. For this purpose, experimental investigations were carried out into replacing the binder material with heated stone powder (HSP), which is released during the drying of aggregates at 150–200 °C in asphalt plants. Also, the effectiveness of using boron minerals in MK-based mixtures was investigated. For this purpose, the most suitable geopolymer mixture design was determined by the Taguchi optimisation method. 10, 20 and 30% HSP were replaced with MK in the mix prepared by the determined optimal rates. In addition, 5, 10 and 15% boron minerals were added to MK-based mixtures. Physical, mechanical and morphological analyses were performed to determine the suitability of the new material. As a result, it was concluded that HSP might be feasible as a retarder and workability agent, and the use of boron minerals as a retarder might be logical.