Physico-mechanical and shielding properties of alkali-activated slag composites incorporating cement clinker aggregate: Effect of high temperature and particle size

Abstract

The purpose of this research was to see how cement clinker aggregates (CCA) and curing temperature affected the physico-mechanical and shielding properties of alkali-activated composites (AAC) exposed to high temperature. The precursor used to create AAC was ground blast furnace slag (GBFS), which was activated using a solution of sodium silicate (Na2SiO3) and sodium hydroxide (NaOH). Quarts powder with a size range of 0–0.5 mm and CCA in two different size ranges (0–4 mm and 4–8 mm) were used as fine and coarse aggregates in the fabrication of AAC. Four different AAC mixes were produced which were cured by three curing temperatures at 25 °C (air curing), 40 °C, and 80 °C for 8 h. The impacts of curing temperature and CCA size and content were examined on the AAC's flowability, compressive strength, flexural strength, porosity, dry unit weight, and water absorption and sorptivity characteristics. The high temperature performance and shielding properties of the produced blends was also assessed. Microstructure investigations of AAC mixtures produced within the scope of the study were also carried out based on FTIR and SEM. The obtained results implied that compressive strength of up to 80.80 MPa was attained with the use of CCA at curing temperature of 80 °C. The M4 containing the highest CCA content with the sizes of 4–8 mm and the lowest CCA content with the sizes of 0–4 mm exhibited the lowest strength at all curing temperatures. All AAC mixes regardless of curing temperature lost more than 60% of their initial compressive strength after 300 °C. Finally, among the AAC mixtures, whose gamma-ray shielding properties were examined in the photon energy range of 81–661 keV and whose fast neutron dose rates were determined, 0–4 mm particle size Clinker doped M1 sample showed better nuclear shielding ability compared to other mixtures studied.