Strength of interparticle bonds in soil pastes and aggregates

The dynamics of the strength of the soil structure in the course of drying of soil pastes and aggregates have been studied in a loamy gray forest soil using the cone-plastometer method suggested by Rebinder. It is shown that the paste consistence and the corresponding rheological model can be determined from the paste strength loading curves at different values of the moisture content. The dynamics of the strength of the structural bonds in both the pastes and the aggregates are nonuniform and depend on the prevailing forms of soil water. The strength of the soil pastes considerably exceeds the strength of the natural aggregates in the range of moisture contents from the hygroscopic moisture to the liquid limit. This is caused by the more dense packing of the soil particles and, hence, more intensive interparticle interaction. The ratio of the aggregate strength to the paste strength upon equal levels of moistening makes it possible to quantitatively compare the strengths of the interparticle bonds in aggregates and pastes.