Morphology and fines type effect on packing of binary soils

Three sands with different particle shapes were mixed with non-plastic fines and plastic fines (clay), respectively, in an entire fines content from 0 % to 100 %. Test results on determining the maximum and minimum void ratios show that both the particle shape of host material and the plasticity of fines can delay the onset of the threshold fines content. For a given fines type in binary soils, the threshold fines content decreases linearly with increasing overall regularity of host material, which proves the feasibility of overall shape parameter in describing soil properties. Meanwhile, the linear equation considering two parameters was derived from test data to evaluate the variation of the maximum and minimum void ratios with increasing fines content by volume for sand-fines mixtures, and the effects of shape of sand and plasticity of fines on the two parameters were investigated. Moreover, non-linear or higher degree equations considering two boundary conditions may have a better per-formance on describing the variation, but some limitations still exist.

Automated summary

Three sands with different particle shapes were mixed with non-plastic fines and plastic fines (clay) in various fines content. The results showed that both the particle shape of the host material and the plasticity of fines can affect the threshold fines content. The linear equation derived from the test data can evaluate the variation of void ratios with increasing fines content, but some limitations exist.