MICROSTRUCTURE OF A COMPACTED SILT

This paper presents a qualitative and quantitative study of the micros tructure of a compacted silt, carried out using a scanning electron mi croscope and mercury intrusion pore size distribution measurements. Sa mples have been statically compacted at three water contents: on the d ry side of the standard Proctor optimum water content, at the optimum, and on the wet side. The wet sample has a matrix type structure, with a clayey fraction filling the voids and adhering to the silt-sized gr ains, whereas the other samples display a structure characterized by a skeleton made of silt grain aggregates linked together by clayey brid ges. The distribution of water and air within the microstructure of th e compacted soil is described for each of the three compaction states.