Author(s)

O. Capobianco, G. Costa & R. Baciocchi

Abstract

This work reports the results of a lab-scale investigation carried out to assess the effects of a stabilization/solidification-granulation treatment applied to an industrial soil sampled from a brownfield site. Preliminary tests were performed on a natural soil to investigate the effects of the operating conditions and mixture formulations on the physical and mechanical properties of the product. In a second phase, the process was tested on the brownfield industrial soil, applying the operating conditions and binder type that provided the best results in the preliminary tests. The suitability of the obtained granules for use as artificial aggregates was assessed through the analysis of the particle size distribution, mechanical strength and inorganic contaminant leaching. With regard to the industrial soil, the best mechanical performance, comparable to that of natural gravel, was achieved with the following mixture formulation: 30% wt. of cement R 52.5, a water/solid ratio equal to 0.14 l/kg and an additive/solid ratio equal to 2 % wt. The alkaline pH of the leachates as well as the leaching behaviour of the cement showed to exert a great influence on the release of some critical metals from the obtained granules, such as Ba, Cr, Mo and Cu. Keywords: brownfields, technology trains, operating windows, aggregates, mechanical properties, inorganic contaminants, leaching.

Keywords

brownfields, technology trains, operating windows, aggregates, mechanical properties, inorganic contaminants, leaching.