In this study, the potential use of industrial waste materials, namely, copper slag (CS), iron ore tailings (IOT), and red mud (RM), as stabilizing agents for black cotton (BC) soil in pavement construction applications was evaluated. Laboratory tests were conducted to assess the performance of the stabilized BC soil, including Atterberg limits, compaction characteristics, California bearing ratio (CBR), unconfined compressive strength (UCS), permeability, and fatigue tests. Additionally, microstructural analysis was performed to further investigate the changes in the soil properties. The results indicated that BC soil mixed with CS, IOT, and RM exhibited enhanced plasticity, strength (UCS and CBR), permeability, and fatigue properties compared to untreated BC soil, regardless of the mix percentage. Notably, BC soil with 30% CS demonstrated comparable results to BC soil stabilized with 5% cement, significantly improving its properties. This study addressed a gap in pavement engineering research by evaluating the fatigue behavior of stabilized subgrade soils. It was concluded that incorporating 30% CS into BC soil not only enhanced its performance but also provided a sustainable alternative to traditional stabilizers such as cement and lime.

Molybdenum ore tailings, iron ore tailings and waste glass powders are important industrial solid wastes, mainly composed of silicate minerals and quartz, which are expected to become alternative resources for inorganic nonmetal industrial materials. In this paper, the ultra-lightweight ceramsite was prepared by the synergistic sintering of molybdenum ore tailings, iron ore tailings and waste glass powders according to their characteristics of silicate minerals. The physical and mechanical properties were investigated when the sintering temperature was between 1100 and 1140 degrees C. The evolution of mineral phases and formation mechanism of pore structure during sintering were studied by XRD, FT-IR, SEM, TG-DSC and HSM. The results showed that in the sintering process, the waste glass powders and the pargasite in iron ore tailings first melted to produce the initial liquid phases. Then the anorthoclase and the quartz in molybdenum ore tailings melted to produce a large amount of liquid phases. These liquid phases covered the gas generated by the oxidation of SiC, thus forming a rich pore structure. At the same time, the [Si2O64-] and Ca2+, Mg2+ in the liquid phases derived from quartz and pargasite melting recrystallized to form diopside, which was conducive to the improvement of mechanical properties of ceramsite. When the raw material ratio of molybdenum ore tailings, iron ore tailings and waste glass powders was 6:2:2 and the sintering temperature was 1120 degrees C, the pore structure of the ceramsite as prepared was uniform and rich and mostly closed. The density was low and the mechanical propertities were excellent. It has a good application prospect in the field of building thermal insulation and sound insulation.

Brazil stands out as one of the largest mineral producers in the world. However, this economically important activity also causes significant damage to the environment. The disposal of mining waste in dams gained great repercussions after the disasters in Mariana, in 2015, and Brumadinho, in 2019, that the need to find a new use for these materials arose. The main objective of the research was to evaluate the addition of iron ore waste to materials used in the base and sub -base layers of road pavements. The results of the mechanical tests demonstrated that it is technically feasible to introduce iron ore waste into the soil-cement mixtures used in the base and sub -base layers. It was found that a minimum of 6% cement in soil-cement mixtures for the base layer, and 5% and 4% for the sub -base layer, are sufficient for the addition of waste. This indicates that waste can be an excellent alternative to reduce cement consumption. This incorporation could reduce the consumption of natural resources, offer an alternative destination for mining waste and even reduce the costs of paving works. With this research, we seek an intelligent and sustainable solution to the impacts caused by mining tailings in Brazil.