Experimental study on contact angle and pore characteristics of compacted loess

To further understand the permeation and pore distribution properties of compacted soil, the contact angle measurements and mercury intrusion porosimetry under different compaction conditions were performed. Experimental results show that the wettability of the compacted loess decreased slightly, but it was not significantly changed when the number of poundings increased from 10 to 75. The contact angle had a significantly linear positive correlation with the dry density and the volume of micropores, whereas it had a linear negative correlation with the total pore volume per unit mass and the volumes of macropores and mesopores. The distribution of different pore sizes varied depending on the compaction process. The macropore volume of the compacted loess samples decreased sharply when the number of poundings increased and almost became zero after 30–40 poundings. The mesopore volume decreased consistently until it reached a steady state. In contrast, the small pore volume increased firstly, reaching the peak value at the 30th–40th pounding, and then decreased until it reached a steady state. Finally, the micropore volume increased slightly at the beginning and then decreased slightly, with a peak value comparable to that of the small pores. During the compaction process of these samples, large deformations occurred when the number of poundings was less than 30–40, and the deformation was mainly caused by the reduction of macropores and mesopores. Relatively small deformations occurred when the number of poundings was greater than 30–40, and the deformation was mainly caused by the reduction of small pores.