Study on the mechanical properties of fiber-modified iron tailings stabilized by lime and fly ash based on energy analysis

Abstract

After being cured by lime and fly ash and then modified by fiber material, waste iron tailings can obtain good road performance, which can not only reduce the accumulation of iron tailings but also save natural resources and can be used as a new road material with good performance. In this study, polypropylene fiber (0 %, 0.25 %, 0.5 %, 0.75 %, 1 %) was added to lime-fly ash solidified iron tailings (LHT) to produce a new type of road composite fiber modified two-ash iron tailings (LHTF). The mechanical properties of LHTF were analysed by unconfined compressive tests and splitting tensile tests, and the optimal ratio of LHTF was obtained. The internal failure mechanism of LHTF was explored and explained by analysing the transformation of the macroscopic failure mode and the change law of the energy absorption capacity of materials. The results show that with increasing fiber content, the unconfined compressive strength, splitting tensile strength and strength gain ratio first increase and then decrease. When the fiber content is 0.75 %, LHTF can achieve the best tension and compression performance and has the largest peak strain. With the increase in fiber content, the failure mode of LHTF gradually changes from brittle failure to ductile failure, and obviously different types of failure characteristics can be seen at the failure interface. The ductility failure characteristics of LHTF with the best fiber content are the most obvious, and the brittleness index is the lowest. The total strain energy density and elastic strain energy density of LHTF first increased and then decreased, while the change law of dissipated energy proportion showed the opposite situation. This study provides a reference for the recycling and utilization of waste iron tailings as road materials.