Recycling of crushed concrete and steel slag in drainage structures of geotechnical works and road pavements

Abstract

A crushed concrete aggregate, processed from construction and demolition waste and a siderurgical aggregate, processed from electric arc furnace steel slag, were selected based on their very high availability worldwide and known technical feasibility to be used in construction works. Given the association of their presence to the possibility of reducing the drainage capacity of unbound granular layers of road pavements and drainage structures which they may be associated with, there are studies and regulations that do not recommend their use. The causes that are at the origin of restrictions are mainly the possibility of formation of tufa and recementation phenomena. This behaviour has also hampered their recycling in drainage structures of geotechnical works. Therefore, it was considered that it would be relevant to investigate the drainage capacity of those recycled aggregates, using a leachate produced in a municipal solid waste landfill and tap water. To reference their behaviour, two natural aggregates, a basalt and a limestone, were also studied under identical test conditions. The results obtained showed no reduction in the drainage capacity of the recycled aggregates, similarly to what was observed with the natural aggregates. The possibility of building drainage structures with the tested aggregates is verified.

Utilization of Natural Soils as a Remediation Method for Electric Arc Furnace and Ladle Slags

“…Experimental studies have indicated that steel slags have the potential to be a suitable replacement for natural aggregates typically used in road filling [5,11,26,[67][68][69] and have sufficient drainage capability [70], resulting in improved performance as the ratio of fine content decreases [71]. However, toxic trace metals released due to high alkalinity cause environmental damage.…”