Assessment of Mechanical Resistance, γ-radiation Shielding and Leachate γ-radiation of Stabilised/solidified Radionuclides Polluted Soils: Preliminary Results

Stabilisation/solidification treatment was performed in order to assess the possibility to remedy radionuclides (Th-232) polluted soils. A sandy soil spiked by thorium oxide (ThO2) at level of 2.2 % was stabilised/solidified using different binder mixture of Portland cement (32.5 Rck and 42.5 Rck) and barite aggregates at different soil: binder ratio (3.3:1 and 4.0:1) and tested for its setting time, unconfined compressive strength (UCS), gamma radiation shielding and contaminant leaching. Results obtained by setting time tests showed that different treatments do not influence the performance of the treatment, whereas the level and the type of cement used significantly influenced the mechanical resistance of the S/S materials. The presence of the barite aggregates mixed with cement gives also a significant containment of the. radiation and an excellent reduction of contaminant leaching but slightly reduce the performance in terms of mechanical resistance, possibly representing an optimal choice to S/S treat low level radionuclides polluted soil. The obtained preliminary results are of scientific and practical interest and may be used for further researches, whereas complete results will represent a suitable tool to optimize the treatment operating conditions and to guide the design and the scale-up of S/S treatment systems of full scale remediation activities of radionuclides polluted soils.