An experimental study on the frost heave properties of coarse grained soils

We investigated the impact of fines content on frost heave and compaction in subgrade construction materials, in order to determine the optimum fines content of coarse-grained soils (CGS) required to achieve reduced frost susceptibility and efficient compaction simultaneously. We conducted laboratory freezing tests simulating thermal conditions in the field, and compared open and closed systems. We studied 47 samples with different fines content, dry density, overburden pressure, and water supply (open or closed) by compaction tests and frost heave tests. Among other significant effects observed, the freezing temperature decreased gradually with incremental increases in the percent content of fines. Fines content proved to be an important factor influencing the amount of frost heave of CGS. Overburden pressure restrained the amount of frost heave to some extent. The frost heave ratio of CGS samples increased first before reaching the peak value of dry density and then decreased. Overall, our results show that the optimum fines content at which the CGS could be compacted effectively with low frost heave susceptibility was 9%. We also conclude that in the field, it is imperative to employ waterproofing and drainage measures.