The collapsibility behavior of fine sand is considered one of the serious geotechnical
problems facing foundations and constructions. One of the commonly used methods for
underlying soil stabilization is compaction. In this study, collapse behavior of compacted fine
sand-bentonite mixtures was investigated. Oedometer tests were carried out to study the effect
of bentonite content on the collapse settlement of compacted fine sand-bentonite mixture.
Samples of fine sand soil were mixed with different amounts of bentonite (0%, 5%, 10%,
15% and 20% by weight of dry fine sand). Maximum dry density (γdmax.) and optimum
moisture content (OMC) were determined for each sample. Soil samples were prepared in
oedometer ring at various compaction degrees (Ic= 90%, 95% and 100%) and OMC. The
collapse potential was determined and investigated under applied pressure of 200 KN/m
2
. The
obtained results indicated that, the collapse potential decreases with the increase of bentonite
content and compaction degree. Moreover, increasing the compaction effort decreases the risk
of fine sand collapsibility.