The effect of aggregations on bimodal kaolinite soils

Abstract

Residual bimodal soils present great complexity of hydraulic and mechanical behaviour, due to the presence of aggregations, mineralogy and complex structures. These soils often present a clear bimodality with a wide difference between the size of intra-aggregate and inter-aggregate pores, of 2 to 3 orders of magnitudes. The objective of this work is to produce a soil with bimodal characteristics using Kaolin Clay, in order to eliminate possible mineralogical, particle size and structural variables, since the clay mineral present in this material is mainly Kaolinite. Analyses of the effect of stable aggregations on soil structural behaviour were carried out by means of soil water retention curve (SWRC). For this, a new methodology was developed for the production of stable aggregations, which were used to compose new bimodal soils. Then, a series of comparisons between the SWRC of the soil with and without aggregation were carried out. Results showed that the presence of aggregations had a direct impact on soil plasticity, particle size classification and compaction curve.