Use of copper slag from an abandoned landfill in asphalt mixes

Abstract

Copper slag is considered a mining environmental liability and is usually deposited in landfills. However, some investigations have been oriented to their use in mortars and concretes. On the other hand, no studies have been reported on the use of copper slag from abandoned landfills of the 19th century in the design of asphalt pavements. In this study, the behaviour of hot asphalt mixtures containing copper slag from abandoned landfill in northern Chile, as a partial substitute for coarse aggregate was evaluated. For the design and control of bituminous pavement mixtures, the Marshall method was used. The parameters evaluated were density, % air voids in the mixture, % voids in the mineral aggregate, creep and stability. In addition, asphalt mixtures containing 4.5 to 6.0% were evaluated with increments of 0.5% asphalt for four types of mixtures with partial substitution of conventional aggregates by copper slag (0, 30, 50 and 70%, by weight). In conclusion, it can be pointed out that the mixture with 5% asphalt and 30% copper slag in replacement of the aggregate is the most suitable mixture and could be used in the design of asphalt mixtures for pavements. The use of copper slag from abandoned landfills in the manufacture of asphalt pavements, would contribute to improving environmental conditions, also decreasing the demand for aggregates in desert areas such as the Atacama Region in Chile.