Soil Improvement with binders addition

Working Group
Tampere University of Technology
Aim of the research work is to improve mechanical and hydraulic behavior of compacted mixtures of soils and binders to be applied in earthworks (e.g. road embankments, river banks), slope stabilization and sidewall liners for controlled landfills.
The binders of concern are lime and cement.
Cement capability of improving shear resistance of soils (irrespective of soil type and as a function of cement amount) is well known, besides this capability also hydraulic conductivity of soils can be reduced or increased by binder addition as a function of soil type and type and amount of cement.
An experimental laboratory study was developed for many soils of different characteristics in order to consider a wide range of grain size distributions and different mineralogy. By means of statistical analysis, a prevision model of hydraulic conductivity as a function of variables linked to mineralogy, grain size characteristics and compaction energy was developed.
The research on lime stabilization is focused on time and mode of reactions between clayey soils and quicklime or hydrated lime, on the analysis of the effect of main variables of lime treatment on mechanical and hydraulic behavior of soils and on long term effect of lime stabilization. The analysis of micro-structure of lime-treated soils has been useful for interpretation of experimental results.
Correlations between shear strength parameters and main variables of lime treatment have been studied in order to optimize the mix-design procedure together with compaction and plasticity characteristics of treated soils.
A feasibility study of the stabilization of sensitive Finnish clay with quicklime has been carried out and is currently in progress.