Lime and cement stabilization is a widely used technique for stabilizing sensitive clay. By mixing binder with clay, the soil shall increase its strength and stability. Upon excavation, lime-cement columns are mixed with the... [ view full abstract ]
Lime and cement stabilization is a widely used technique for stabilizing sensitive clay. By mixing binder with clay, the soil shall increase its strength and stability. Upon excavation, lime-cement columns are mixed with the surrounding non-stabilized materials that, after being disturbed, have weak strength and low stability. Such mixed materials are often disposed in landfills as inert waste.
The possibility of reuse produces a valorization of these materials and reduces the need of disposal areas. This research is part of the project "GEOreCIRC – Georesources in a circular economy" at the Norwegian Geotechnical Institute. The project, financed by the Research Council of Norway, aims to facilitate reuse and utilization of various residual resources in an environmentally satisfactory way.
A number of laboratory tests were carried out to determine the geotechnical parameters of the mixed materials of clay and lime-cement stabilized clay. Both soft and quick clay were included, as these are the most commonly soil materials stabilized with lime and cement.
The laboratory tests results show that mixed materials achieve good values in terms of strength, plasticity, compressibility and hydraulic conductivity.
The tests results show that the mixed materials changes from soft and weak remoulded clay to a material with increased shear strength. The resulting material is compactable and it is possible to spread it out in constructive layers. The material shows good potential for being used in road embankments and landscaping, if it is well blended and processed. It can also serve as a geological barrier and as an impermeable layer in landfills for inert wastes.
The use of the mixed materials as the impermeable layer in landfills for ordinary or hazardous waste is also possible. However, this requires a hydraulic conductivity lower than 10-9 m/s. Test results from this study show uneven hydraulic conductivity values in the order of magnitude of 10-9 m/s, being not conclusive.
Higher hydraulic conductivity values than those in this study were obtained on samples from a test site with earthworks on similar mixed materials of clay and lime-cement stabilized clay. This suggests that construction techniques play an important part to reach the hydraulic conductivity required.
Lessons learnt from practical projects , New products, applications and machinery , Development of design and modelling methods
