Pilot in situ auger mixing treatment of a contaminated site. Part 3. Time-related performance

This paper, part 3 of a series of publications, presents a laboratory assessment of an in situ auger mixing treatment of a contaminated site up to 28 months after treatment. Part 1 detailed the site conditions and treatability study work and part 2 detailed the auger development and the site trial. The laboratory assessment was carried out in terms of physical and chemical properties, namely unconfined compressive strength, durability, permeability, compressibility, leachate pH, X-ray diffraction and scanning electron microscopy. The time-related behaviour of the seven mixes used was investigated and compared at two, 14 and 28 months after treatment and assessed in relation to the design criteria set at 28 days. This paper presents evidence of time-related behavioural changes and of the complexity and site-specific nature of the problem. It also emphasizes the time-liness of research work on long-term behaviour of stabilized/solidified contaminated ground to improve the efficiency and cost-effectiveness of the treatment methodology.