Abstract
Two soils spiked with lead at different rates were stabilised/solidified using Portland cement and fy ash at different soil:binder ratios, and tested for their setting time, unconfined compressive strength, leachability and durability. A performance threshold approach was used in order to identify optimal management options for the products of the S/S treatment. Results show that soil texture, percentage of binders and lead concentration play an important part in the treatment, significantly influencing the performance of the resulting products in terms of curing, compressive strength and durability. Pb soil concentrations higher than 15000 mg kg-1 were found to heavily reduce the applicability of the treatment requiring the maximum amount of binder in order to satisfy the performance criteria. Te performance of sandy soils was shown to be limited by setting time and UCS features due to the retardation of the hydration reactions and also by its leaching behaviour, whereas for silt-clayey soils the critical parameter is the mechanical resistance.
Highlights
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The general objective of this work was to better understand the potential of S/S for the treatment of Pb polluted soils and in particular the effects of Pb concentration and soil:binder ratio on the physical and mechanical properties of soil treated with Portland cement (PC) and Fly ash (FA) which were assessed analysing the setting time, unconfined compressive strength (UCS), leachability and durability of the treatment products
For the other experimental conditions, all the tested samples were disintegrated after 2 cycles, for soils A (S:B 5.0:1) and B (S:B 5.0:1) and after 8 cycles for soil A (S:B 4.0:1). These results clearly show that, despite the overall best durability performance of the sandy soils, at high Pb contamination level, they could be more vulnerable than fine texture soils such as soil B
Summary
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