Stabilisation of clayey and marly soils using industrial wastes: pH and laser granulometry indicators

• A study into both clayey and marly soil stabilisation is presented.
• Industrial by-products were used as non-conventional additives.
• The effectiveness of these agents was analysed from a laboratory study.
• Residual dolomitic lime can be as effective as commercial lime.
• Steel slag is presented as a promising agent for soil stabilisation.

The use of non-conventional additives in soil stabilisation has increased significantly in recent years. Nevertheless, the effectiveness of alternative additives, which can be determined by the impact promoted on the pH of the soils, could be limited due to insufficient time for the pozzolanic reaction (associated with a quick decrease of pH). Thereby, this paper focuses on the study of the efficacy of using different dosages of innovative industrial wastes in both clayey and marly soils. The additives studied were dolomitic lime (from residual quarry sludges), biomass fly ash, steel slag (from Electric Arc Furnace), and conventional lime which was used as a control. The effectiveness of these additives was evaluated by measuring the evolution of pH, carbonate content and particle size at 0, 7, 14 and 28 days. Results showed that residual dolomitic lime can be as effective as commercial lime in soil stabilisation, while the biomass ash used in this work was found to be the least effective additive. All additives used in this study led to greater changes in soil properties for clayey samples.