Investigation of usability of quarry dust waste in fly ash-based geopolymer adhesive mortar production

Crushed-stone dust is a harmful waste product of crushed-stone aggregate concrete production. It has no added value and is disposed of by washing in well-organized facilities. This study experimentally investigated the geopolymer-based adhesive mortar in order to use crushed-stone dust as a building material at the best rates. Fly ash (FA) was used as the geopolymer binder and sodium silicate (SS) and NaOH were used as alkali activators. NaOH was used in three different molarities (3M, 6M and 12M). Two different materials were used as adhesive mortar mineral filler: 100% quarry dust and quarry dust mixed with silica sand at a ratio of 1/3. Geopolymer adhesive mortars were cured in an oven at 80 degrees C for 1, 3 and 5 h. Bulk density, apparent density, water absorption, apparent porosity, capillary water absorption, compressive strength, flexural strength, tensile adhesion and rheology experiments were performed on adhesive mortar specimens. All series had higher tensile adhesive strength than the standard. 100% of the waste material was used with the binder and mineral filler, and 33% silica sand addition made a positive contribution to some mortar properties. (C) 2019 Elsevier Ltd. All rights reserved.