Determination of the expansion potential and processes of the sandstone (greywacke)-shale wastes

AVCI E., TUĞRUL A., Yorukoglu A.

BULLETIN OF ENGINEERING GEOLOGY AND THE ENVIRONMENT, vol.81, no.7, 2022 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 81 Issue: 7
  • Publication Date: 2022
  • Doi Number: 10.1007/s10064-022-02787-9
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, IBZ Online, Aerospace Database, Aquatic Science & Fisheries Abstracts (ASFA), CAB Abstracts, Communication Abstracts, Compendex, Environment Index, Geobase, INSPEC, Metadex, Pollution Abstracts, Civil Engineering Abstracts
  • Keywords: Expanded clay aggregates, Clay minerals, Greywacke, Waste recycling, Expansion, Dehydroxylation, THERMAL-DECOMPOSITION, LIGHTWEIGHT, CLAY, SLUDGE, TEMPERATURE, AGGREGATE, FLUIDS, MELTS, ASH
  • Istanbul University Affiliated: No


Materials with grain sizes of less than 63 mu m from the quarries (Cebeci, Cendere and Arnavutkoy) in Istanbul (Turkey) are considered as waste and cannot be utilised in any area. In this study, we aimed to determine the expansion potential of the wastes and the factors that trigger the expansion. The grain sizes of the sandstone-shale wastes from the Cebeci (CB), Cendere (CN) and Arnavutkoy (AR) quarries range between 2 and 71 mu m, 2 and 56 mu m and 2 and 77 mu m, respectively. The mineral paragenesis of the wastes from the investigated regions is the same and consists of quartz, albite, muscovite, chlorite and calcite. Expansion tests show that quarry waste samples expanded at temperatures between 1200 and 1210 degrees C. The wastes were subjected to expansion tests in the range of 2-8 min, and their expansion rates were determined every minute. It was determined that the expansion rate of the quarry wastes in the Cendere region is higher than those of the Cebeci and Arnavutkoy regions. Thermal analysis results indicate that the OH? release (dehydroxylation) of chlorite and muscovite minerals in waste samples occurred at approximately 560 degrees C. As a result of dehydroxylation, the wastes undergo partial melting and thus form a viscous structure that can trap gases and provide expansion in the samples. With the formation of a viscous structure, H2O and CO2 gases released from chlorite, muscovite, calcite minerals and organic matter in the range of 1200-1210 degrees C were trapped in the samples and allowed them to expand.