Construction and works

LURMASA

ON-SITE STABILISATION OF CONTAMINATED SOILS TO PRODUCE REUSABLE MATERIALS

SINCE THE CONSTRUCTION OF LOGISTICS-PORT AND INDUSTRIAL INFRASTRUCTURES (DOCKS, SEAWALLS, DOCKYARDS, ETC.) requires huge amounts of construction materials, industrial byproducts, such as steel slag, are often used as fi ller materials, and this can cause soil contamination issues with heavy metals. Soil management work in these sites generates large quantities of excavated materials, which normally end up in landfi ll sites. The Port of Bilbao has used over 400,000 tonnes of iron and steel aggregate in infrastructures in a controlled manner since 2008, although new technologies are currently required to recover earth mixed with this aggregate.

AFESA is a leading company in waste management, soil treatment and demolition.

AFESA
OBJECTIVES
  • Develop an innovative on-site treatment process to stabilise and solidify soils contaminated with heavy metals and fi lled with non-hazardous steel slag.
  • Create a safe building material, similar to soilcement or gravel-cement, which can be reused on the same site as the materials from which it was made.
  • Obtain mineral binders and additives that reduce the permeability of the material, as well as leaching of heavy metals, providing the material with some self-sealing capacity.
RESULTS
  • Identification and use of combinations of cement and mineral materials that improve performance (reducing crack formation and permeability, etc.) compared to that obtained exclusively using cement.
  • Identification of other variables essential to improve equipment performance.
  • Reduced cement consumption in the formulations used by partially replacing it with materials with a lower carbon footprint.
CONCLUSIONS
  • Once selectively excavated, non-hazardous industrial materials that have been used as backfill, can be re-used as raw material for on-site manufacture of durable and recyclable soil-cement or gravelcement pavement.
  • This practice would avoid sending it to landfill and at the same time reduce the need to use quarried aggregates.
  • LURMASA has implemented a technically and economically feasible solution, but requires regulatory evolution in the Basque Country.

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