Investigation of Mode II Fracture Behavior of Alkali-Activated Mine Tailings

Asadizadeh M.; Hedayat A.; Tunstall L.; Neira T.M.; González V.J.A.; Alvarado V.J.W. · 57th US Rock Mechanics/Geomechanics Symposium (2023) · DOI: 10.56952/arma-2023-0844

Resumen

Reuse of mine tailings (MTs) rich in aluminum oxide and silicon dioxide to produce a geopolymer using an alkali activator is a sustainable approach to reduce the MTs' environmental hazard. The fracturing behavior of mine tailing-based alkali activated materials under mode II loading has been largely unexplored. In this study, the mode II fracture tests have been adopted to examine the double-edge notched Brazilian disk (DNBD) geopolymer specimens under diametral loading. A mixture of MTS (85% wt.), class F fly ash (FA) (15% wt.), and 10 M NaOH solution with solid/liquid ratio of 14% was prepared, and using a cylindrical mold, specimens were cast and then cured at 70 °C. Mode II fracture toughness, the evolution of the crack tip opening and sliding displacement and the shear and minimum principal strain behavior were examined through strain mapping using the Digital Image Correlation (DIC) technique. The results showed that although DNBD is intended to provide pure mode II loading, mixed mode fracturing was observed, as there was still some crack surface opening. The study highlights the need for further investigation to fully understand the nature of mixed-mode fracture behavior in DNBD specimens and its implications for material characterization.

Instituciones: Universidad Nacional de Trujillo