For expansive soils like bentonite should we go for heavy
compaction or standard proctor compaction? Why?
1. Many researchers have given the values of OMC and MDD for bentonite-based buffer
materials corresponding to heavy compaction (higher compaction energy).
2. he swelling potential of expansive soils increases with the increase in dry unit weight and
reduces with the do crease in water content. Therefore, less density and higher water content
is recommended. However, expansive soils always must be treated before use in construction
otherwise seasonal changes i would definitely reveals their heave potential
3. The main engineering use of bentonites is to isolate municipal or hazardous wastes. For high
level radioactive waste, high density and high bentonite content are appreciated since they
yield very low hydraulic conductivity. The generated swelling pressure will be taken by the rock
surrounding the canisters.
On the other hand, for near surface disposal like the case in landfills, a lower bentonite content
is usually advised due to construction difficulties and high swelling pressure that require a thick
overburden to balance the upcoming pressure upon wetting. Keeping in mind high dry density
to enhance shear strength and creep.
To sum up, you have to balance between bentonite content, dry density, swelling pressure,
shear strength and creep, these are project dependent.
4. Heavy compaction of expansive soil may lead to higher swelling potential, It is better to use
light compaction, at water content wet of optimum.
5. It is better to use light compaction because low density result in low swelling potential
6. Light compaction should be used "Standard Compaction Energy". Good Luck